Force/Motion Quick Review

Force and Motion Review

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Multiple Choice

Forces can cause objects to

• stop moving only.

• start moving only.

• start moving, change direction, or stop moving.

• change direction only.

Forces

• Forces can stop - pushing, pulling, friction, gravity

• Change Directions- think about hitting a baseball.

• Change from potential to Kinetic (moving)

Multiple Choice

According to Newton's third law of motion, when a hammer strikes and exerts force on a nail, the nail

• disappears into the wood.

• exerts an equal force back on the hammer.

• creates a friction with the hammer.

Newton's Laws

• 1st Law- Objects in motion will stay in motion; objects at rest will stay rest.

• 2nd Law- More mass needs more force/ more force = more acceleration.

• 3rd Law - For every action, there is an equal and opposite reaction.

Multiple Choice

Jasmyn can run 50 yards in 10 seconds and Jaylah can run 100 yards in 20 seconds. Who has a faster speed? (Remember speed equals distance divided by time.)

• They both have the same speed.

• Jasmyn

• Jaylah

50/10 = 5 = 100/20

Both have a quotient of 5.

Multiple Choice

The tendency of an object to stay in motion or at rest until a force acts upon it is

• frame of reference

• movement

• inertia

• relation

Multiple Choice

The direction of the frictional force on a moving object is...

• never responsible for stopping the motion of the object.

• opposite to the motion of the moving object.

• the same as the motion of the moving object.

• not going to alter the acceleration of the moving object.

Friction

One surface or object rubbing against another.

High Friction surface examples: Sandpaper, Grass, Carpet, rough surface

Low Friction- Hardwood floors, ice, smooth surfaces

Multiple Choice

Distance divided by time describes

• speed

• Acceleration

• velocity

• momentum

Distance Time Graphs

Multiple Choice

Which of the following is an example of increasing friction intentionally?

• adding grease to gears on a bike

• throwing sand on an icy driveway

• waxing skis

Friction Reduced or Increase

• Increase friction because the surface is unsafe or get a better grip - cleats or sand

• Decrease friction to go faster- like waxing skis or greasing gears

Multiple Choice

An object that has kinetic energy must be...

• lifted above earth's surface.

• at rest

• in motion.

• none of the above

Potential vs. Kinetic

Potential- The higher- the more potential

Kinetic is moving.

Think of a Roller Coaster
Getting to the very top is the Potential
When you are flying down the roller coaster that is the kinetic.

Multiple Choice

Based on Newton’s first law of motion, what happens when you slide forward on ice?

• You will lose your balance and fall over before you reach the middle.

• You will continue to slide until a force makes you stop or change direction.

• Gravity keeps you moving until someone makes you stop.

• The size of your ice skates affects your speed across the ice.

Multiple Choice

How is velocity different from speed?

• Velocity is when an object goes in reverse.
• Velocity is the direction an object moves in, and it has nothing to do with speed.
• Velocity is speed and direction together.
• Velocity is not at all different from speed.

Multiple Choice

What does friction do to a moving object?

• slows it down

• speeds it up

• makes it rise

• all of the above

Multiple Choice

What needs to happen to a soccer ball for it to return to someone?

• Friction has to be applied to the ball.

• Force has to be applied to the ball.

• Speed has to be applied to the ball.

• Inertia has to be applied to the ball.

Multiple Choice

What is the relationship between heavy objects and inertia?

• Only heavy objects have inertia.
• Heavy objects have no inertia.
• Heavy objects have less inertia.
• Heavy objects have more inertia.

Multiple Choice

You are riding in the car with your grandfather, and he turns left. Why do you shift to the right?

• It takes you a moment to catch up with the new velocity of the car.
• You have more inertia than the car, so it takes longer for you to turn left.
• You had been sitting at rest until the force of the turn set you in motion.
• The car continued in the same velocity, but you had a different inertia.

Multiple Choice

What does the second part of Newton’s first law say about objects at rest?

• They cannot move unless they have a lot of friction.
• If they are heavy, they will stay at rest, but if they are light, they will move.
• They will stay at rest unless an outside force makes them move.
• They have more inertia than objects in motion.

Multiple Choice

Your neighbor is riding her bike around the block. When she slows down and turns a corner, what changes about her?

• her velocity
• her friction
• her speed only
• her balance

Multiple Choice

What is the rate at which an object’s velocity changes called?

• inertia

• actualization

• acceleration

• completion

Multiple Choice

What is inertia?

• the amount of force to start moving an object at rest

• an object’s velocity and its friction

• what keeps an object steady, at rest or moving consistently

• the friction needed to slow an object in motion

Multiple Choice

Your skateboard begins to slow down when you roll off the sidewalk and across gravel. What is at work?

• gravity
• friction
• balance
• all of the above

Multiple Choice

What can be measured by acceleration?

• how much an object slows down
• how much an object speeds up
• an object’s change in direction
• all of the above

Multiple Choice

Your dog’s wagging tail knocks over the cup of pencils sitting on your desk. What kind of force is his tail?

• an unbalanced force
• an inert force
• gravitational force
• friction

Multiple Choice

If a hockey stick acts on a resting puck, what will happen?

• The puck will remain inert and the hockey stick will accelerate.
• The puck will balance on the end of your hockey stick until you drop it.
• The hockey stick will not move the puck, but the puck will move the hockey stick.
• The hockey stick will change the speed of the puck and make it accelerate

Multiple Choice

Every time your cat’s paw hits her toy string, it swings away from her. How does this demonstrate Newton’s third law of motion?

• Objects with mass, such as your cat’s paw and toy string, will require inertia.
• Objects in action, such as the string toy, will experience force.
• For every motion from your cat’s paw, there is unbalanced inertia from the string.
• For every action your cat makes, there is an equal and opposite reaction from the string

Multiple Choice

What happens when two objects, such as a baseball and a bat, collide?

• One remains still while the other one moves in the same direction.
• They hit each other with the same force in opposite directions.
• They hit each other with unequal force in opposite directions.
• They hit each other with the same force in the same direction.

Multiple Choice

What does an object do when it accelerates?

• It speeds up.
• It moves in the opposite direction.
• It changes speed and direction.
• all of the above

Multiple Choice

What determines an object’s mass?

• amount of matter
• amount of friction
• amount of force
• amount of gravity

Multiple Choice

When two objects with unequal mass collide, what happens?

• accelerate at different rates

• accelerate in the same direction

• come to a complete stop

• continue at the same velocity

Multiple Choice

A softball and a volleyball collide with equal speed, and then they accelerate at the same rate. What must be true about the masses of the objects?

• The softball has more mass than the volleyball.
• The softball and the volleyball have equal mass.
• The volleyball has more mass than the softball.
• It is impossible to compare the mass of the softball and the volleyball

Multiple Choice

During P.E., your soccer ball collides with the goalie. What happens to the soccer ball?

• It stops moving completely.
• It accelerates at the same rate and in the same direction as the goalie.
• It accelerates more and in a different direction than the goalie.
• It continues moving at the same velocity as before.

Multiple Choice

When you jump off a small rowing boat onto the shore, the boat moves backward. Which of Newton's laws explains this action?

• Newton's First Law of Motion

• Newton's Second Law of Motion

• Newton's Third Law of Motion

• Newton's Law of Universal Gravitation

Multiple Choice

If you were to push a shopping cart with twice the force you used before, what would happen to the acceleration of the cart?

• The acceleration would decrease.

• The acceleration would stay the same.

• The acceleration would double.

• The acceleration would be halved.

Multiple Choice

What does the gravitational force between two objects depend on?

• The mass of the first object only

• The mass of both objects and the distance between them

• The distance between the objects only

• The speed at which the objects are moving towards each other