Physics Review Kinematics & Dynamics

Physics Review Mechanics

Kinematics and Dynamics

​Position, Distance, and Displacement​

• Position is a location that can be described by coordinates (x,y)​

• Distance is measurement between two positions​

Examples:  Walking from home (zero) to the school and back 1000 m   ​

 Or  ​

   Falling from a plane (zero) to the ground 30,000 ft below.​

• Displacement is a change in position of an object. It is independent of the path taken. Displacement is given the designation s, Dx Dy or Dz​

• No displacement from home!  Blown out of straight line by the winds as the object falls.​

• Speed is a scalar quantity describing distance traveled in a specified time.​

• Average Speed = Total distance /  total time​

• Scalar quantities have magnitude only.​

​​speed

• Velocity is a vector quantity. It describe displacement with relation to time. ​

• Vector quantities have magnitude and direction.​

• V = s/t = Dx/Dt = vf +vi / 2 ​

• Average Velocity need not equal average speed.​!

​​Velocity

​Graphing Velocity

• The slope of a line on a position-time graph is the average velocity.​

• The slope of a tangent is the instantaneous velocity.​

• The area under the line on a velocity- time graph gives the displacement.​

• Vectors can be added or subtracted graphically or by breaking each vector into components and adding or subtracting components and then using Pythagorean theorem.​

​​Vector Math

• If the stream is 120 m wide how long will it take the person to get across the stream?​

• Remember that the person is rowing straight across at a rate of 8.0 km/hr. ​

• V = 8km/hr   d = 0.120 km ​

• v = d/t  ​

• Vt = d  ​

• t = d/v​

• t =  0.120 km/8 km/hr​

• t = .015 hr (60min/hr) = 0.9min​

• The problem is that the person will not end up directly across from where they started unless they compensate for drift.  They will be 90 m down stream.​

  ​

• When acceleration is constant and in a straight line we call it uniform linear acceleration.​

• Rearranging the equation for average velocity we get  vf = v0 +at.​

• In this case average and instantaneous velocity are equal.​

​Uniform linear acceleration

• Acceleration is a change in velocity over a specified time period.​

• aavg = vf-vo  / t.​

• A negative sign indicates acceleration in the negative direction or a deceleration.​

• If v and a are the same the object is accelerating if they are different it is decelerating.​

• The slope of a velocity time graph gives the average acceleration.​.

​Acceleration

ACCELERATION

• If the acceleration is in the positive direction and slowing down or in the negative direction and speeding up then acceleration is negative.

• If the acceleration is positive direction and speeding up or negative and slowing down then the acceleration is positive.  ​

SIGNS OF ACCELERATION

Remember that x is displacement- it can be in the x, y, or z directions.

If displacement is in the y direction a is g or 9.81m/s^2

DERIVED EQUATION

Free Fall

• When an object falls with acceleration due to gravitational force and experiences no other significant forces this is known as free-fall​

• Earth’s gravitational force causes free-fall at the rate of 9.8 m/s2​

• DIRECTION must be defined at the beginning of each problem and by convention we assign up as positive; therefore acceleration due to gravity is  -9.8 m/s2 and is designated g​

Frame of reference is determined by the choice measurement being compared to.  If applying Newtons laws the inertial frame of reference must be used.

​Relative Frame of reference (if you throw a ball up while on a turning bus it will not come down where expected).

Inertial frame of reference (not accelerating or rotating)​​

​Frame of Reference

• A Projectile is any object that is thrown by any means.  There are 3 basic situations:  objects thrown vertically​

• Objects thrown horizontally from a height, and objects thrown at an angle​

• Key concepts are:  horizontal movement is totally independent of vertical movement, both movements are vector quantities, the velocities are perpendicular to each other, there is a resultant velocity.​

​2 D Kinematics

• Objects that are thrown or launched follow a two-dimensional path known as a trajectory.  ​

• Because the vertical and horizontal motion of a projectile are independent of each other we can analyze them separately using equations for linear velocity and acceleration.

PROJECTILES

2 D Motion

• Any object that follows a curved path with a vertical and horizontal change in velocity is known as a projectile and the motion is projectile motion.​

• If air resistance is neglected, the initial and final horizontal velocity are equal and the angle of projection equals the angle of impact.​

• Projectiles follow a parabolic path.

  PROJECTILE MOTION

  ​p

• A projectile launched at 30⁰ with an initial velocity of 10 m/s.  Its horizontal velocity is  10 m/s (cos 30⁰) = 8.7 m/s.

This is the horizontal velocity of the projectile throughout the trajectory.

• The horizontal velocity of a projectile remains constant if air resistance is neglected.​​

​Vx = x/t.

Horizontal  Motion of a Projectile​
The horizontal component, x, is constant like the motion on a surface. (V_h or V_x are used for horizontal velocity.  If we ignore air friction the horizontal velocity applied to the object at the start will remain unchanged unless acted on by another object or force)​

• v_ix = v_fx   a_x = 0                        x =  v_x t​

Verticle components of Projectiles

• These projectiles have highly symmetric characteristics of motion.​

• Definition: The trajectory is the path traveled by any projectile. It is plotted on an x-y graph.​

• Mathematically, the path is defined by a parabola.​

• Definition: The RANGE of the projectile is how far it travels horizontally.​

• The MAXIMUM HEIGHT of the projectile occurs when it stops moving upward. ​

​For a projectile launched over level ground, the maximum height occurs halfway through the flight of the projectile Launch angle is symmetric with landing angle for a projectile launched over level ground.​

• Acceleration points down at  9.8 m/s2 for the entire trajectory of all projectiles.​

Resolve the vector into its components 1st.

v becomes
v_x cos Θ
v_y sin Θ

• Change in angular position.​

• s = Δθ r

​1 rev = 360⁰ = 2πrad     θ is described in radians by definition

θ = s/r where s is the arc length and r is the radius

Linear & Angular Analogy

Multiple Choice

Which description best describes the velocity of an object in uniform circular motion?

• It changes magnitude and is tangent to the circle.

• It constantly changes magnitude and direction.

• It changes direction and is tangent to the circle.

• It changes magnitude and is towards the center of the circle.

Multiple Choice

A 12.0 g rubber ball on the end of a 0.75 m string is swung in a horizontal circle. It travels at 3.4 m/s.

What is the centripetal acceleration of the ball?

• $$15\ \frac{m}{s^2}$$  

• $$4.5\ \frac{m}{s^2}$$  

• $$0.18\ \frac{m}{s^2}$$  

• $$41\ \frac{m}{s^2}$$  

Multiple Choice

Two bowling balls each have a mass of 6.8 kg. The balls are 0.218 m apart.

What is the gravitational force between the two bowling balls?

G = 6.67 x 10^-11

• $$6.5\ x\ 10^{-8}\ N$$  

• 1 N

• $$4\ x\ 10^{-9}\ N$$  

• $$1.03\ x\ 10^{-8}\ N$$  

Multiple Choice

A runner is running around a circular track. The track has a diameter of 15 meters. How many meters, in total, does the runner run when it completes one loop?

• Depends on how long it takes him to run the loop

• 47.12 meters

• 94. 94.25 meters

• 176.71 meters

Multiple Choice

What effect does changing the length of a pendulum have on its period?

• The period increases with increasing length

• The period decreases with increasing length

• The period remains the same regardless of the length

• The period is unpredictable with changing length

Multiple Choice

What is the period on Earth of a pendulum with a length of 2.4 m?

• 3.1 sec
• 1.9 sec
• 9.3 sec
• 5.1 sec

Multiple Choice

The time that it takes to complete one wave cycle is called the...

• frequency
• period
• amplitude
• wavelength

Multiple Choice

The number of cycles that are completed per second is called the _ and is measured in _.

• frequency, Hertz
• wavelength, meters
• amplitude, meters
• period, seconds

Multiple Choice

The value of g for Jupiter is 24.79 m/s². What is the period of a pendulum that has a length of 2.00 meters?

• 1.78 s

• ‭2.52 s

• 44.2 s

• 1.26 s

Multiple Choice

If a pendulum has 20 J of potential energy at point 1, how much kinetic energy will it have a point 3?

• 0 J

• 10 J

• 20 J

• 30 J

Multiple Choice

Where does a pendulum have maximum kinetic energy?

• at the bottom of its arc

• at the end of its swing

• as it rises up

• as it falls

Multiple Choice

A spring oscillates 555 times in 13.2 seconds. What is it's frequency?

• 42 Hz

• 0.02 Hz

• 31 Hz

• 26 Hz

Multiple Choice

What is the period of a pendulum on a 0.12 m long string with a 2 kg mass attached to it?

• 0.69 s

• 1.54 s

• 1.44 s

• 0.039 s

Multiple Choice

A spring has a spring constant of 6 N/m. If a force of 2.5 N is used to stretch the spring, how far does it stretch?

• 0.81

• 15 m

• 2.4 m

• 0.42 m

Multiple Choice

A spring is compressed a distance of 9.56 m, using a force of 272 N. What is the spring constant of this spring?

• 0.04 N/m

• 28.45 N/m

• 2600 N/m

• 51.27

Multiple Choice

A spring starting at the resting position is compressed a distance of 0.87m. If the spring constant is 1500 N/m, what is the work required to compress the spring?

• -461 J

• -284 J

• +567 J

• +782 J

Multiple Choice

What is the work required to stretch a spring 0.67 m if it has a spring constant of 412 N/m from it's resting position?

• +92.47 J

• -92.47 J

• +0.01 J

• -0.01 J

Multiple Choice

What is the direction of a centripetal force?

• In the same direction that the object is moving
• Inward and perpendicular to the motion of the object
• Upward and slightly forward
• Outward and perpendicular to the motion of the object

Multiple Choice

A small but hard nut must be crushed.  Which position will require more squeezing force by a hand?

• Position A
• Position B
• It doesn't matter which position the nut is in.

Multiple Choice

Find the magnitude of the torque formula if produced by a 22.0 N force applied to a door at a 30 degree from the perpendicular distance of .005 km from the hinge.

• T=Frsin𝞡

• T=Frcos𝞡

• Tnet=0

• T/r=F

Multiple Choice

A wrench is used to tighten a nut. A 15N perpendicular force is applied 50cm away from the axis of rotation, and moves a distance of 10 cm as it turns. What is the torque applied to the wrench?

• 7.5 Nm
• 1.5 Nm
• 750 Nm
• 150 Nm

Multiple Choice

When an object is experiencing a net torque

• it is in dynamic equilibrium.
• it is in static equilibrium.
• it is rotating.
• it is translating.

Multiple Choice

If the torque required to loosen a nut on the wheel of a car has a magnitude of 60.0 N• m, what minimum perpendicular force must be exerted by a mechanic at the end of a 45.0 cm wrench to loosen the nut?

• .666 Nm
•  133.3 N
• 66.7 N
• 13.3 Nm

Multiple Choice

A circular object of radius R has an angular velocity of k rad/s. The angular velocity at a point R/2 is:

• 2k rad/s

• k/2 rad/s

• k² rad/s

• k rad/s

Multiple Choice

A force of 50-N is applied to a 4 kilogram mass. The acceleration of the object is:

• 200 m/s²

• 12.5 m/s²

• 54 m/s²

• 46 m/s²

Multiple Choice

A 5 kg ball is lifted 12 m above the ground. It's gravitational potential energy is

• 60 J
• 600 J
• 17 J
• 2.4 J

Multiple Choice

Name the missing force

• weight

• normal force

• applied force

• friction

Multiple Choice

As the angle of the incline increases, what happens to the normal force?

• The normal force increases

• The normal force decreases

• The normal force is not affected by the incline

• The normal force is only dependent on the force due to gravity

Multiple Choice

Which of the following is true about the system shown?

• The system is not accelerating.
• The tension between m₂ and m₁ is less than the tension between m₂ and m₃
• The acceleration of the system only depends on m₃
• None of the other answers are true

Multiple Choice

Which of the following is not true about the system?

• T₃ is equal to the scalar sum of the magnitudes of T₂ and T₁

• T₃ is equal in magnitude to F_g

• The x- components of the T₁ and T₂ and equivalent but in opposite directions

• The system is in equilibrium.

Multiple Choice

A man standing on a scale in an elevator notices that the scale reads 40 newtons greater than his normal weight. Which type of movement of the elevator could cause this greater-than-normal reading?

• accelerating upward

• accelerating downward

• moving upward at a constant speed

• moving downward at a constant speed

Multiple Choice

SI unit for distance

• miles

• centimeters

• meters

• inches

Multiple Choice

A stone is falling through the air. The acceleration of free fall is 10 m/s². Ignoring air resistance, what happens to the stone each second during its fall?

• The acceleration of the stone increases by 10 m/s².

• The speed of the stone increases by 10 m/s.

• The stone travels a distance of 10 m.

• The stone travels at a speed of 10 m/s.

Fill in the Blank

What is the acceleration of the object that is speeding up? (include units)

Multiple Choice

Given the FBD, which of the following must be true?

• The frictional force must be accelerating the system to the left.

• The box must be accelerating to the right.

• The box must be moving to the right.

• The FBD is incorrectly drawn. This situation isn't possible

Fill in the Blank

What is the acceleration of the object that is slowing down? (include units in your answer)

Multiple Choice

A mass of 2.5 kg falls from rest. It would be correct to say that _______________.

• it falls with a constant acceleration of 25 m/s²

• it falls with a constant acceleration of 10 m/s²

• it falls with a constant acceleration of 4 m/s²

• it falls with a constant velocity of 10 m/s²

Fill in the Blank

What is the distance travelled by the object that made this graph? (include units in your answer)

Multiple Choice

SI unit for time

• seconds

• minutes

• hours

• days

Fill in the Blank

What is the distance travelled by the object that made this graph? (include units in your answer)

Multiple Choice

An object  accelerates at 2  m/s^2. Assuming the object starts from rest, how much time does it need to accelerate to a speed of 16  m/s?

• 4 s
• 8 s
• 16 s
• 1/16 s

Multiple Choice

What is the magnitude and direction of the net force?

• 10 N to the Right

• 10 N to the Left

• 0 N

• 8 N to the Left

Multiple Choice

An airplane lands on a runway with a velocity of 150 m/s. How far will it travel until it stops if its rate of deceleration is constant at -3 m/s²?

• 525 m
• 3750 m
• 6235 m
• 9813 m

Multiple Choice

Formula for velocity

• v = d*t

• v = d/t

• v = m*t

• v = m/t

Multiple Choice

An object with an initial velocity of 3.50 m/s moves east along a straight and level path. The object then undergoes a constant acceleration of 1.80 m/s² east for a period of 5.00 s. How far does the object move while it is accelerating?

• 6.30 m
• 17.5 m
• 27.2 m
• 40.0 m

Multiple Choice

If you exert a force of 20 N to push a desk 10 m, how much work did you do to the desk?

• 20 N
• 200 N
• 200 J
• 2 J

Multiple Choice

A dog runs with an initial speed of 7.5 m/s to a stop in 15 seconds.  What is the dog's acceleration?

• -7.5 m/s
• -7.5 m/s²
• -0.5 m/s²
• 7.5 mi//hr

Multiple Choice

Formula for acceleration

• a = (vf-vo)/t

• a = t/(vf-vo)

• a = t*(vf-vo)

• a = t*d

Multiple Choice

A golf ball starts with a speed of 2 m/s and slows at a constant rate of 0.5 m/s², what is its velocity after 2 s?

• 0 m/s
• 0.5 m/s
• 1 m/s
• 1.5 m/s

Multiple Choice

Calculate the net force acting upon the object.

• 10N, north

• 20N, south

• 10N, south

• 22.4N, north

Multiple Choice

A roller coasters accelerates from an initial velocity of 6.0 m/s to a final velocity of 70 m/s over 4 seconds.  What's the acceleration?

• 24 m/s²
• 18 m/s²
• 16 m/s²
• 16 m/s

Multiple Choice

SI unit for mass

• kilograms

• grams

• pounds

• ounces

Multiple Choice

A car is traveling at 21.0 m/s. It slows to a stop at a constant rate over 5.00 s. How far does the car travel during those 5.00 seconds before it stops? 

• 4.20 m
• 52.5 m
• 105 m
• 158 m

Multiple Choice

By what factor will the kinetic energy of an object increase if the velocity of the object is tripled?

• The kinetic energy will stay the same.

• 3

• 6

• 9

Multiple Choice

An object  accelerates at 2  m/s^2. Assuming the object starts from rest, how much time does it need to accelerate to a speed of 16  m/s?

• 4 s
• 8 s
• 16 s
• 1/16 s

Multiple Choice

SI unit for force

• Joules

• Watts

• Newtons

• meters

Multiple Choice

The sum of all forces acting on an object is called:

• Contact Force

• Balanced Force

• Unbalanced Force

• Net Force

Multiple Choice

Formula for force

• F = m*a

• F = m/a

• F = d*a

• F = d/a

Multiple Choice

Which has a greater momentum a semi-truck at rest or a bicycle in motion?

• truck
• bicycle
• neither has momentum
• same

Multiple Choice

SI unit for energy

• Joules

• Watts

• Newtons

• meters

Multiple Choice

An object in motion...

• must have balanced forces

• must have unbalanced forces

• must be accelerating

• will stay in motion unless acted on by an unbalanced force

Multiple Choice

Formula for work

• W = F*d

• W = F/d

• W = F*m

• w = F/m

Multiple Choice

Which of the following is true about the system shown?

• The system is not accelerating.
• The tension between m₂ and m₁ is less than the tension between m₂ and m₃
• The acceleration of the system only depends on m₃
• None of the other answers are true

Multiple Choice

Formula for kinetic energy

• KE = m*g*y

• KE = $$\frac{1}{2}$$ m*v^2

• KE = F*d

• KE = W/t

Multiple Choice

Name the missing force

• Friction

• Gravity

• Applied force

• Normal force

Multiple Choice

Formula for potential energy

• U = m*g*y

• U = $$\frac{1}{2}$$ m*v^2

• U = F*d

• U = W/t

Multiple Choice

On a graph showing distance versus time, a horizontal line represents an object that is

• moving at constant speed
• decreasing its speed
• increasing its speed
• not moving

Multiple Choice

Formula for spring constant

• k = -F/d

• k = F/d

• k = -F*d

• k = F*d

Multiple Choice

What is the net force of the block?

• 8N, right

• 2N, right

• 8N, left

• 2N, left

Multiple Choice

Formula for elastic potential energy

• Us = m*g*y

• Us = $$\frac{1}{2}$$ k*x^2

• Us = F*d

• Us = W/t

Multiple Choice

An object is thrown vertically upward with an initial speed of 15 m/s. What is the total time in the air?

• 3 second

• 1.5 seconds

• 5 seconds

• 3.5 seconds

Multiple Select

Formula for total mechanical energy

• TME = Ki-Kf+Ugi-Ugf+Usi-Usf+W

• TME = W

• TME = Ki+Kf+Ugi+Ugf+Usi+Usf+W

• TME = Ki-Kf-Ugi-Ugf-Usi-Usf-W

Multiple Choice

If there are two forces pushing an object in the same direction, how do you find the net force on the object?

• Subtract

• Add

• Multiply

Multiple Choice

SI unit for power

• Watts

• Joules

• Newtons

• Meters

Multiple Choice

In a speed vs. time graph, a straight line shows that acceleration is

• decreasing
• increasing
• constatnt
• zero

Multiple Choice

Formula for power

• P = W/t

• P = E/t

• P = W*t

• P = E*t

Multiple Choice

What is force?

• A push exerted on an object

• A push or pull exerted on an object

• A pull exerted on an object

• What an object feels

Multiple Choice

Definition of work

• The amount of energy transferred when an object is moved over a distance by an external force in regards to the direction of the displacement.

• The rate of energy transferred per second

• The amount of energy transferred in motion

• The amount of energy an object has at rest / before motion

Multiple Choice

Which of the following statements is true about the image above?

• The accelerations of the blocks will vary according to their mass

• The net force acting on each block is the same

• The blocks will experience the same acceleration

• The 3m box will eat the 2m and the m boxes

Multiple Choice

Definition of power

• The amount of energy transferred when an object is moved over a distance by an external force in regards to the direction of the displacement.

• The rate of energy transferred per second

• The amount of energy transferred in motion

• The amount of energy an object has at rest / before motion

Multiple Choice

The force that pulls objects toward the Earth

• Speed

• Gravity

• Normal

• Thrust

Multiple Choice

Definition of kinetic energy

• The amount of energy transferred when an object is moved over a distance by an external force in regards to the direction of the displacement.

• The rate of energy transferred per second

• The amount of energy transferred in motion

• The amount of energy an object has at rest / before motion

Multiple Choice

A person has a mass of 24 kg on Earth. What is the persons mass on the Moon (1/6 of Earth's gravity)?

• 24 kg
• 144 kg
• 6 kg
• 4 kg

Multiple Choice

Definition of potential energy

• The amount of energy transferred when an object is moved over a distance by an external force in regards to the direction of the displacement.

• The rate of energy transferred per second

• The amount of energy transferred in motion

• The amount of energy an object has at rest / before motion

Multiple Choice

Given the FBD, which of the following must be true?

• The frictional force must be accelerating the system to the left.

• The box must be accelerating to the right.

• The box must be moving to the right.

• The FBD is incorrectly drawn. This situation isn't possible

Multiple Choice

An 8-kg object is raised by a crane to the top of a building 20-meters in height. If it takes 50 seconds for the object to get to the top of the building, then how much power was needed?

• 1600 watts

• 3.2 watts

• 32 watts

• 200 watts

Multiple Choice

Which of the following statements is true about the image above?

• The accelerations of the blocks will vary according to their mass

• The net force acting on each block is the same

• The blocks will experience the same acceleration

• The 3m box will eat the 2m and the m boxes

Multiple Choice

When you know speed and direction you know

• force
• acceleration
• velocity
• momentum

Multiple Choice

Sam is hover boarding down they hall at a constant velocity. Assuming there is friction, which of the following must be true?

• The force applied by the board must be greater than the frictional force

• The frictional force must equal the force applied by the board

• The force applied must equal zero

• There is not enough information

Multiple Choice

Which of the following is not true about the system?

• T₃ is equal to the scalar sum of the magnitudes of T₂ and T₁

• T₃ is equal in magnitude to F_g

• The x- components of the T₁ and T₂ and equivalent but in opposite directions

• The system is in equilibrium.

Multiple Choice

A 80 kg skydiver is free falling at a constant velocity of 19 m/s. What is the net (total) force acting on her?

• 1,520 N
• 0 N
• 4.21 N
• Not enough information to answer

Multiple Choice

What is the horizontal acceleration of a projectile?

• 0 m/s²
• 9.8 m/s²
• 4.9 m/s²
• -9.8 m/s²

Multiple Choice

"If we apply a ___________ to an object, its __________________ will change and it will  ______________."

• force, accelerate, gravity
• accelerate, inertia, gravity
• force, velocity, accelerate
• velocity, gravity, inertia

Multiple Choice

A kg-m²/s² is otherwise known as a(n)

• Newton

• Joule

• Watt

• Displacement

Multiple Choice

The more mass an object has, the faster it will fall.

• True
• False

Multiple Choice

A man standing on a scale in an elevator notices that the scale reads 40 newtons greater than his normal weight. Which type of movement of the elevator could cause this greater-than-normal reading?

• accelerating upward

• accelerating downward

• moving upward at a constant speed

• moving downward at a constant speed

Multiple Choice

What determines the strength of gravitational attraction between two objects?

• mass and distance
• size and mass
• density and mass
• density and size

Multiple Choice

If the gravitational force between two masses is F, then by what factor would the distance between the two object need to change if the mass of one of the objects is doubled in order for the force to remain the same?

• 4

• 2

• 2^1/2

• 6^1/2

Multiple Choice

What is Newtons 2nd law?

• Kinetic Energy = 1/2mv²
• Work = Force x distance
• Force = Mass x Accelaration
• gravitational potential energy = mass x gravity x height

Multiple Choice

A man weighing 800 Newtons is standing in an elevator. If the elevator rises with an acceleration of 0.5 meters per second², the force exerted by the elevator on the man will be

• 400 N

• 800 N

• 1200 N

• 1000 N

Multiple Choice

Kinetic Energy is defined as

• Energy stored due to its location
• Energy of motion
• Energy stored in the bonds of molecules
• Heat energy

Multiple Choice

A rocket of mass m begins to ascend vertically at v m/s. The work that gravity does on the rocket is:

• Negative

• Zero

• Positive

• Undefined

Multiple Choice

Which of the following objects has the most kinetic energy?

• A 20 kg toddler running at 5 m/s
• A 50 kg toddler running at  30 m/s
• A 90 kg toddler running at 30 m/s
• A 100 kg  toddler running at 2 m/s

Multiple Choice

A car travels up a hill at constant speed. Which of the following diagrams best represents the forces acting on the car at this instant?

Multiple Choice

two objects with mass are separated a distance of r.  if the mass of one doubles, the force of gravity between them

• doubles
• gets cut in half
• triples
• does not change

Multiple Choice

The area under a force-time curve represents:

• Change in potential energy

• Change in momentum

• Change in force

• Change in torque

Multiple Choice

the velocity of an object is 12 m/s.  what will the displacement be in 2 seconds?

• 12 m
• 24 m
• 36 m
• no idea

Multiple Choice

"If we apply a ___________ to an object, its __________________ will change and it will  ______________."

• force, accelerate, gravity
• accelerate, inertia, gravity
• force, velocity, accelerate
• velocity, gravity, inertia

Multiple Choice

Charlie Holloway is launched out of a cannon with a speed of 40 m/s at 45 degrees with respect with the ground.  Which of the following is true about Charlie's acceleration at the highest point in his trajectory if air resistance is negligible?

• the acceleration is unknown
• the acceleration is horizontal
• the acceleration is straight down
• the acceleration is straight up

Multiple Choice

A circular object of radius R has an angular velocity of k rad/s. The angular velocity at a point R/2 is:

• 2k rad/s

• k/2 rad/s

• k² rad/s

• k rad/s

Multiple Choice

is it possible for forces to act on an object and still have a net force of zero?

• yes
• no
• depends on the type of force

Multiple Choice

The magnitude of the horizontal component of F is:

• $$F_{x\ }=30\ N$$  

• $$F_{x\ }=40\ N$$  

• $$F_{x\ }=3\ N$$  

• $$F_{x\ }=4\ N$$  

Multiple Choice

You drop a 5 kg ball from a height of 2 m. Just before it reaches the ground, what type of energy does it have?

• Potential Energy
• Kinetic Energy
• Nuclear Energy
• Chemical Energy

Multiple Choice

Two forces are acting on an object; a horizontal force of 8.3 Newtons and a vertical force of 5.4 Newtons. The magnitude of the resultant force is about:

• 13.7 Newtons

• 2.9 Newtons

• 9.9 Newtons

• 6.3 Newtons

Multiple Choice

If you throw a baseball straight up, what is its velocity at the highest point?

• 9.8 m/s²
• 9.8 m/s
• 0 m/s
• 4.9 m/s

Multiple Choice

What is impulse?

• force done on an object
• Inertia in motion
• Change in momentum
• Amount of energy possessed by an object.

Multiple Choice

The magnitude of the vertical component of F is:

• $$F_{y\ }=30\ N$$  

• $$F_{y\ }=40\ N$$  

• $$F_{y\ }=4\ N$$  

• $$F_{y\ }=3\ N$$  

Multiple Choice

Motion sensors recorded the following data about a runner during a cross-country race. During which segment of the race did the runner have the greatest speed?

• W
• X
• Y
• Z

Multiple Select

If a system is in static equilibrium, it must have the following 2 conditions:

• ∑τ=0

• Constant acceleration

• ∑F=0

• Positive forces only

Multiple Choice

What happens to the velocity of a ball as it is dropped off a cliff? 

• It decreases at a uniform rate 
• It increases at a uniform rate 
• It is constant 
• It increases at a non-uniform rate

Multiple Choice

A horizontal, uniform board of weight 125 N and length 4 m is supported by vertical chains at each end. A person weighing 500 N is sitting on the board. The tension in the right chain is 250 N. What is the tension in the left chain?

• 250 N

• 375 N

• 500 N

• 625 N

• 875 N

Multiple Choice

In the absence of air friction, an object thrown into the air will return to the ground with ______ it was thrown up at.

• a greater velocity than
• a lesser velocity than
• the same velocity

Reorder

Rank the magnitude of the torque the signs exert about the point at which the rod is attached to the side of the building. From Greatest to Least.

• B

• D

• C

• A

1

2

3

4

• 1
• 2
• 3
• 4

Multiple Choice

Superman exerts a force on 5N on Batman's hand. What is the force that Batman's hand exerts on Superman's?

• Greater than 5N
• Less than 5N
• Equal to 5 N
• Taha's does not exert a force on Rushi's

Multiple Choice

As the angle of the incline increases, what happens to the normal force?

• The normal force increases
• The normal force decreases
• The normal force is not affected by the incline
• The normal force is only dependent on the force due to gravity

Multiple Choice

A block of weight W is pulled along a horizontal surface at constant speed v by a force F, which acts at an angle Θ with the horizontal, as shown. The normal force exerted on the block by the surface has magnitude_____.

• greater than W

• greater than 0 but less than W

• equal to W

• 0

Multiple Choice

Which of the following is not a necessary step in the problem solving strategy?

• Free Body Diagram
• Find the components of the forces
• Determine or not the system is in equilibirum
• All steps are completely necessary

Multiple Choice

Taylor wants to test the effect of friction. She places a block on a plank and raises one end so that the plank is inclined. What is the maximum angle that incline can have before the block begins to accelerate if the coefficient of friction is 0.7?

• 46°

• 10°

• 35°

• 44°

Multiple Choice

The Earth pulls downward on a pingpong ball with a force  of 1N. If this is the "action" force, what is the "reaction" force?

• The ground exerts a force of 1N on the ping pong ball
• The ping pong ball exerts a force of 1 N on the Earth
• The ping pong ball pushes down on the earth with a force of 1N
• The is no reaction force when a gravitational force is involved

Multiple Choice

Rank the tensions experienced by the strings.

• T_A > T_B > T_C

• T_B > T_A = T_C

• T_B > T_C > T_A

• Cannot be determined

Multiple Choice

Given the FBD, which of the following must be true?

• The frictional force must be accelerating the system to the left.
• The box must be accelerating to the right.
• The box must be moving to the right.
• The FBD is incorrectly drawn. This situation isn't possible

Multiple Choice

Refer to the picture to answer the following question. If M = 1kg, what is the acceleration of the masses? Assume the surface is frictionless.

• a = 4.67m/s²

• a = 6.67m/s²

• a = 2.67m/s²

• a = 1.33m/s²

Multiple Choice

Which of the following is true about the system shown?

• The system is not accelerating.
• The tension between m₂ and m₁ is less than the tension between m₂ and m₃
• The acceleration of the system only depends on m₃
• None of the other answers are true

Multiple Choice

Refer to the picture to answer the following question. If M = 1kg, what is the tension in the rope? Assume the surface is frictionless.

• F_T = 20.0N

• F_T = 0.67N

• F_T = 10.7N

• F_T = 13.3N

Multiple Choice

Will launches a catapult that changes the velocity of a ball (m= 2 kg) from 0 to 10 m/s. What is the average force that is exerted on the ball during launch?

• 20 N
• 5 N
• 8 N
• 0.2 N

Multiple Choice

Two pendulums are in simple harmonic motion.  Pendulum A is longer than pendulum B.  Pendulum A has a larger mass than B.  The period of pendulum A is

• longer than pendulum B
• shorter than pendulum B
• the same as pendulum B
• not enough information

Multiple Choice

Newton's First Law states....

• an object wants to maintain its motion
• if the forces are balanced, then the velocity will change
• a block will accelerate if a force acts upon it.
• F=ma

Multiple Choice

A pendulum swinging with a maximum amplitude of π/6 has a period of T. If the maximum amplitude is increased to π/3, what is the new period of the pendulum?

• T/4

• T/2

• T

• 2T

Multiple Choice

Which of the following is not true about the system?

• T₃ is equal to the sum of the magnitudes of T₂ and T₁
• T₃ is equal in magnitude to F_g
• The  x- components of the T₁ and T₂ and equivalent but in opposite directions
• The system is in equilibrium.

Multiple Choice

The energy contained in a pendulum depends on its
I. period
II. amplitude
III. mass

• I only
• II only
• II and III only
• I, II, and III

Multiple Choice

The acceleration of an object is proportional to ...

• the net force acting upon it
• its position
• its velocity
• its mass

Multiple Choice

Which position shows the spring with maximum kinetic energy?

• A
• B
• C
• D

Multiple Choice

Which of the following is considered a Field Force?

• Friction
• Normal
• Tension
• Gravity

Multiple Choice

A spring-block simple harmonic oscillator is set up so that the oscillations are vertical. The period of the motion is T. If the spring and block are taken to the surface of the Moon, where the gravitational acceleration is 1/6 of its value here, then the vertical oscillations will have a period of

• $$\frac{T}{6}$$  

• $$\frac{T}{3}$$  

• $$\frac{T}{\sqrt[]{6}}$$  

• T

Multiple Choice

Raymond is hover boarding down the hall at a constant velocity. Assuming there is friction, which of the following must be true?

• The force applied by the board must be greater than the frictional force
• The frictional force must equal the force applied by the board
• The force applied must equal zero
• There is not enough information

Multiple Choice

A block with a mass of 20 kg is attached to a spring with a spring constant k = 50 N/m. What is the magnitude of the acceleration of the block when the spring is stretched 4 m from its equilibrium position?

• 4 m/s²

• 6 m/s²

• 8 m/s²

• 10 m/s²

Multiple Choice

A block with a mass of 4 kg is attached to a spring on the wall that oscillates back and forth with a frequency of 4 Hz and an amplitude of 3 m. What would the frequency be if the block were replaced by one with one-fourth the mass and the amplitude of the block is increased to 9 m?

• 4 Hz

• 8 Hz

• 12 Hz

• 24 Hz

Multiple Choice

If the speed of an object is doubled, its kinetic energy will be ____.

• halved
• doubled
• quadrupled
• quartered

Multiple Choice

An object with a mass of 3 kg has a momentum of 75 kg*m/s. What is its velocity?

• 0.4 m/s
• 7.1 m/s
• 25 m/s
• 72 m/s

Multiple Choice

• A
• B
• C
• D

Multiple Choice

A 20 kg object strikes the ground with 1,960 J of kinetic energy after falling from rest.  How far off the ground was the object when it was released?

• 10 m
• 14 m
• 98 m
• 200 m