Motion unit Review

Motion, Forces and Simple Machines Unit Review

By Ms. Taylor

Speed-distance travelled over time. Measured usually in m/s

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Velocity-Speed in a given direction.

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Acceleration-Change in velocity over time. Caused by change in speed or direction​. Measured in m/s²

​Some text here about the topic of discussion.

​Kinematics

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Multiple Choice

What is the speed of an object that travels 20 meters in 4 seconds?

• 80 m/s
• 0.2 m/s
• 5 m/s
• 24 m/s

Multiple Choice

Kira jogs to a store 72 m away in a time of 36 s. What is Kira's average speed?

• 0.5 m/s
• 2 m/s
• 2 h

Multiple Choice

Gizmo was sitting in the yard. He saw a rabbit and ran after it. After 5.2 seconds his velocity was 6.8 m/s. What was his acceleration?

a= V (end) - V (start)

time

• 1.30 m/s/s

• 1.3 m/s/s

• 0.76 m/s/s

• 35.4 m/s/s

Multiple Choice

Shona cycles at an average speed of 8km/h. How far has she travelled if she cycles for 4 hours?

• 55km
• 32km
• 43km
• 32miles

​Ensure that you look at the labels on axes!!

The slope of a distance-time graph gives velocity.

The slope of a speed-time graph gives acceleration!​

Multiple Choice

What is happening in this graph from point B to C?

• The object is going down a hill.
• The object is returning to its starting location.
• The object is slowing down.
• The object is staying still.

Multiple Choice

This graph shows an object that is _____.

• increasing speed

• maintaining a constant speed

• decreasing speed

• stationary

Multiple Choice

Which line represents an object moving at a faster speed?

• A
• B

Multiple Choice

The graph shows Tom's speed for the first 18 seconds of his journey to school. What is happening at 12 to 18 seconds into his trip?

• He is speeding up

• He is slowing down.

• He is coming to a stop.

-Balanced forces are equal and act opposite to each other giving no motion.

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-Unbalanced forces have a net value of more than 0 so causes motion.​

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​-All object with a mass has a force of gravity. The larger the mass and the closer the objects, the greater will be its force of gravity (hence we are attracted to the earth and not each other).

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-Objects of similar size/shape will experience similar force of gravity regardless of mass and fall from same height at same time.

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-If same mass, but different surface area, objects will fall at different rate. Smaller first

-Force = mass multiplied by the acceleration​

Forces and Gravity

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Multiple Choice

Two factors effecting the magnitude of the force of gravity between 2 objects are...

• Mass and Distance 
• Mass and Matter
• Distance and Weight 
• Weight and Mass

Multiple Choice

Ben conducted an experiment where he drops a bowling ball and an apple from a third-story window. Both objects hit the ground at the same time. From this experiment Ben should conclude that

• the apple weighs more than the bowling ball

• gravity pulls on both objects, causing them to fall at the same time.

• more air friction is acting on the apple than on the bowling ball

Multiple Choice

What is the net force?

• 3 N

• 3 N, right

• 17 N, right

• 3 N, left

Multiple Choice

In the district finals, Vanessa kicks the 0.600 kg soccer ball with a force of 80 N. How much does she accelerate the ball?

• 122 m/s/s

• 50 m/s/s

• 133 m/s/s

• 48 m/s/s

-First law also called law of Inertia.

-Inertia is the tendency of a body to resist change​.

-The greater the mass, the more force needed and smaller the acceleration​.

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-Forces act in pairs that are equal in size but opposite in direction​

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Multiple Choice

Which one of Newton's laws is shown

• 3rd law

• 2nd law

• 1st law

Multiple Choice

Which of Newton's laws is shown

• 1st law

• 3rd law

• 2nd law

Multiple Choice

If there is a big mass, it would need a stronger force to accelerate it. Which law does this describe?

• 3rd law

• 1st law

• 2nd law

Multiple Choice

A magician pulls a tablecloth out from under dishes and glasses on a table without disturbing them.

• Newton's 1st Law
• Newton's 2nd Law
• Newton's 3rd Law

Multiple Choice

Earth exerts a stronger gravitational force than the moon because Earth has more________.

• stuff

• mass

• density

• gravity

Multiple Choice

You push against a wall and the wall is pushing back on you.

• Newton's
  1st
  Law of Motion
• Newton's
  2nd
  Law of Motion
• Newton's
  3rd
  Law of Motion

-Work is the use of force to move an object over a distance in the direction of the force.

-Work =Force multiplied by distance.

-Work is measured in Joules.

-Simple Machines make work easier by either changing direction of applied force, reducing the force needed or increasing distance over which work is done​.

​-Examples: Fixed pulleys change direction, inclined planes, screws, wedges and levers increase distance, movable pulleys multiply force applied.

Work and Simple Machines

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Multiple Choice

You have to push with 15 N of force to move it 10 meters. How much work do you do?

• 15 Joules

• 150 Joules

• 1.5 Joules

• .67 Joules

Multiple Choice

500 J of work is done by a person who uses a force of 50N to move a box, how far does it go?

• 10 m

• 0.1 m

• 25,000 m

• 10 J

Multiple Choice

For work to be done on an object, the direction and force have to be going the same direction.

• True

• False

Multiple Choice

How can simple machines make work easier?

• by decreasing the force needed to complete the task

• by increasing the friction between the machine and the object

• by adding more work on the object than originally applied

• by removing the force of gravity on the object

Multiple Choice

Simple machines can make work easier by reducing the input force needed to move an object. However, there is a trade off for decreased input. What is the trade off?

• The distance the object is moved is increased.

• The distance the object is moved is decreased.

• The amount of work is increased.

• The amount of work is decreased.

​-This is how many times the machine multiplies the input force to make work easier.

-MA= Output force/input force​

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​- Movable pulleys, to get input force, find the MA by counting the supporting ropes (or number of movable pulleys) then divide the mass by that number​.

-Levers, MA increases if fulcrum is closer to load than the effort force applied.​ M

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​Mechanical Advantage

Multiple Choice

What is the mechanical advantage of this pulley?

• 1

• 2

• 3

• 4

Multiple Choice

What is the mechanical advantage of this pulley?

• 4

• 5

• 6

• 7

Multiple Choice

If the weight of the block is 10N, how much force does one have to apply to lift it using this pulley (MA=2)?

• 2N
• 5N
• 10N
• 15N

Multiple Choice

In the diagram how much force must the man be exerting?

• 100 Newtons

• 85 Newtons

• 110 Newtons

• 0 Newtons

Multiple Choice

How can you decrease the effort force needed to push a weight to the top of the ramp? 

• cover the surface with carpet
• increase the length of the ramp
• increase the height of the ramp
• decrease the length of the ramp

Multiple Choice

How does a single fixed puled, like the one seen here, help you do work?

• changes the direction of the force
• increases the amount of applied force
• decreases the amount of applied force
• allows you to pull the rope a shorter distance

Multiple Choice

Jeff is a landscaping contractor and lifts a rock weighing 600 pounds by wedging a board under the rock. Jeff weighs 150 pounds and puts all of his weight on the lever. How much mechanical advantage did the lever provide to Jeff in lifting the rock?

• 0
• 2
• 4
• 8

Multiple Choice

What is the mechanical advantage of the block and tackle used to lift the bale of cotton?

• 1
• 2
• 3
• 4

Multiple Choice

To lift a load off the ground, the force required is equal to the weight of the load. In case of a lever, however, a small effort force can be used to lift a much heavier load. How is this possible?

• Levers use the weight of the load combined with the effort to lift the load.
• Levers combine the weight of the load with the force of gravity to lift the load.
• Levers reduce the force required by increasing the distance over which the force is applied.
• Levers distribute the load over their length, thereby reducing the force required to lift the load.

Multiple Choice

This 2000 N weight is raised 1 meter by pulling 4 meters of rope. What force was required to pull the rope?

• 500 N
• 1000 N
• 2000 N
• 8000 N