Chapter One -Forces

Chapter One -Forces

Things you will be Tested On:

1) Calculating Speed, Velocity, Acceleration, Mass, and Force. And Net Force 
2) Newton's 3 different laws (know definitions and how to identify and explain which law is being demonstrated
3)How to read motion graphs
4) Experimental Variables (Independent, dependent, and Controls)

Identifying Units

• m/s2 is Acceleration

• kilograms(kg) or grams(g) is Mass

• Newtons (N) is Force (also used for weight b/s weight is controlled by the force of gravity)

• m/s is Speed and Velocity (but Velocity must also have a direction)

• Meters (m) is distanceSeconds (s) is Time

Multiple Choice

Which of the following is mass?

• 2 m/s

• 4s

• 25 meters

• 56g

Multiple Choice

Which of the following is Velocity?

• 2 m/s

• 200 meters

• 40 m/s North

• 35 m/s2

Multiple Choice

Which of the following is a measurement of Force?

• 250 kg

• 500 m/s

• 24 mph

• 55 N

Some Equations to Know 

• Speed= distance/Time

• Velocity= distance/ Time  (add direction)

• Force = Mass x Acceleration

• Mass = Force/ Acceleration
  

• Acceleration = Force/ Mass

• Acceleration= (final speed - first speed)/ Time

Multiple Choice

A compact car with a mass of 1,000 kg is accelerating due north at 5 m/s2. What is the force produced by this acceleration?

• 200 N

• 5000 N

• .005 m/s

• 200 kg

Multiple Choice

If a car travels 400m in 20 seconds how fast is it going?

• 80000 seconds

• 20 mph

• 20 m/s

• 5 m/s

Multiple Choice

How much time will it take for a bug to travel 5 meters across the floor if it is traveling at 1 m/s?

• 5 seconds

• 5 hours

• 5 m/s2

• 5 kg

Calculating Net Force

• Watch the Video to Review How to Calculate net Force.

Multiple Choice

What is the net force acting on the box?

• 2 N Right

• 2 N Left

• 6 N Right

• 6 N Left

Multiple Choice

What is the net force acting on the box?

• 8 N Left

• 2 N Left

• 8 N Right

• 2 N Right

Multiple Choice

What is the net forces acting on this box?

• 2 N Right

• 6 N Right and 2 N Up

• 2 N Right and 2N Down

• 2 N Left

Multiple Choice

If forced are balanced......

• the object will move quickly

• the object will move slowly

• the object will move up and down

• the object will NOT move at all

Multiple Choice

Which of the following shows balanced forces?

NEWTONS 1st LAW- INERTIA

• An object in motion wants to stay in motion and an object at rest wants to stay at rest, unless acted on by an outside force.

• Be sure to watch VIDEO!!! :)

Multiple Choice

Which of the following demonstrates the first Law?

Multiple Choice

If an object is moving at a constant speed in one direction, what is needed to change its speed or direction?

• a balanced force

• an unbalanced force

• a short period of time

• a long period of time

Newton's 2nd Law

• An objects acceleration depends on its mass and the force being applied

• F= M x A

Multiple Choice

What is the net force acting on Tim?

• 80 newtons downward

• 625 newtons upward

• 0 newtons

• 705 newtons downward

Multiple Choice

If there are no forces pulling the sled backward, what is the net force acting on the sled?

• 177 N forward

• 267 N forward

• 0 N

• 205 N forward

Multiple Choice

An object's motion changes

• only when a nonzero net force is applied to the object.

• only if the object is at rest when a force acts upon it.

• when the forces acting on the object remain balanced.

• when there are no forces acting upon it.

Multiple Choice

In a football game, a defensive lineman exerts a force upon an offensive lineman, causing the offensive lineman to be accelerated backward at 2 m/s². If the offensive lineman's mass were doubled, how much force would the defensive lineman have to apply to accelerate the offensive lineman 2 m/s² backward?

• twice as much

• the same amount

• half as much

• four times as much

Multiple Choice

Which object will experience the greatest acceleration?

• X

• W

• Y

• Z

Multiple Choice

Wyatt pulls on a sled that his friend is sitting on until the sled just begins to move. His friend and the sled have a combined mass of 80 kg. What is the acceleration of Wyatt’s friend and the sled? A = Force/mass HINT:Find net force, then divide by the mass.

• 5 m/s²

• 8 m/s²

• 3 m/s²

• 10 m/s²

NEWTONS 3rd LAW

• For every action there is an equal and opposite reaction.

• Be sure to watch the video

Multiple Choice

If the man's feet pushing the paddle board is the action force, then which of the following is the REACTION force?

• water pushing up on the paddle board

• the paddle board pushing back on the man's feet

• the paddle board pushing down on the water

• water pushing up on the man's feet

Multiple Choice

When the balloon is released, air is pushed out by the balloon. Which other force is acting that demonstrates Newton's third law of motion?

• Gravity is helping to move the balloon in the same direction.

• The air is pushing back on the balloon in the opposite direction.

• The air is pushing back on the balloon in the same direction.

• The weight of the balloon pushes it in the opposite direction.

Multiple Choice

According to Newton's third law of motion, which of the following best describes the forces of the tennis racket and the ball?

• The tennis racket applies a greater force on the ball than the ball applies on the racket.

• Both the tennis racket and the ball experience equal forces but in opposite directions.

• Neither the tennis racket nor the ball experiences the force of gravity.

• Both the tennis racket and the ball experience equal forces in the same direction.

Multiple Choice

Tom is teaching Jenny how to ice skate. Both skaters, who are about the same size, are on the ice and wearing their skates. To help Jenny get started, Tom gives her a gentle push from behind. Which of the following best describes what will happen next?

• Jenny will move forward, and Tom will not move.

• Jenny will move backward, and Tom will move forward.

• Jenny will move forward, and Tom will move backward.

• Jenny will not move, and Tom will move backward.

Multiple Choice

The wall pushes back against Elizabeth's hands with the same force in the opposite direction. Which of Newton's laws does this best demonstrate?

• Newton's universal law of gravitation

• Newton's third law of motion

• Newton's second law of motion

• Newton's first law of motion

MOTION GRAPHS

• WATCH VIDEO

• Remember to always read the x and y axis of a graph so you know what you are looking at. 

Multiple Choice

How long did it take this object to travel 10 m?

• 0 s

• 10 s

• 15 s

• 20 s

Multiple Choice

At 60 seconds, how far had this object traveled?

• 0m

• 10m

• 20m

• 40m

Multiple Choice

What is represented by this graph?

• constant speed

• speed increasing

• not moving

• speed increasing at a constant rate

Multiple Choice

What is happening at E?

• Stationary

• Accelerating

• Constant speed; moving away from the starting position

• Constant speed; returning to start position

Multiple Choice

What is happening at C?

• Stationary

• Accelerating

• Constant speed; moving away from the starting position

• Constant speed; returning to start position

Multiple Choice

What happened during C to D point?

• not moving

• moving at a constant speed

• increasing speed at a constant rate

• moving at 0 m/s² acceleration

Multiple Choice

What happened during E to F point?

• not moving

• moving at a constant speed

• increasing speed at a constant rate

• moving at 0 m/s² acceleration

Multiple Choice

What happened during B to C point?

• at rest

• moving at a constant speed

• deceleration

• acceleration

Multiple Choice

Which line represents an object moving at a faster speed?

• A

• B

Multiple Choice

Which line represents an object moving at a slower speed?

• A

• B

Multiple Choice

This graph demonstrates an object that is -

• Increasing speed

• Decreasing speed

• At a constant speed

• Stationary

Multiple Choice

This graph demonstrates an object that is -

• Increasing speed

• Decreasing speed

• At a constant speed

• Stationary

VARIABLES

• INDEPENDENT (the one you change on purpose) (only one thing)

• DEPENDENT (the one you measure)

• Controls (things you keep the same) (there are many of them)

• BE SURE TO WATCH THE VIDEO

Multiple Choice

This variable in an experiment is the one being changed by the scientist.

• dependent variable

• independent variable

• data

• control group

Multiple Choice

What is a hypothesis?

• A hypothesis is the right answer to an experiment.

• A hypothesis is the wrong answer to an experiment.

• A hypothesis is an educated guess.

Multiple Choice

Dependent variable is

• an educated guess

• being measured

• being changed on purpose

Multiple Choice

If I ride my bike to school instead of walking, then I will get to school faster. What is the dependent variable?

• How fast you get to school

• Riding a bike or walking

• The type of bike

• the weather

Multiple Choice

If I study more for my test, then I will have a better test score. What is the dependent variable?

• Studying

• Test score

• classroom

• pencil used

Multiple Choice

What is the DEPENDENT variable (effect) in this experiment?

"Does eating breakfast improve test score?"

• eating breakfast or not

• the grade you got on the test

• what time you get up in the morning

• how tasty the breakfast is

Multiple Choice

What is the INDEPENDENT variable (cause) is this experiment?

"Which type of medium is best for plant growth?"

• height of plant (cm)

• amount of medium

• type of medium (soil vs. sand)

• types of plant

Multiple Choice

What is the INDEPENDENT variable (cause)in this experiment?

"Which type of metal, copper or aluminum, conducts heat faster?"

• size of metal

• time it takes to heat up

• types of metal

• shape of the metal

Multiple Choice

What is the INDEPENDENT variable (cause) in this experiment?

"Will fish school more if a predator is present?"

• whether there is a predator or not

• number of fish school together

• type of predator

• type of fish

Multiple Choice

. Mr. S set up an experiment to see how the mass of a ball affects the distance it rolls off a ramp. What is the dependent variable?

• Distance traveled by the ball

• How fast the ball went down the ramp

• Mass of the ball

• Height of the ramp