8th Grade 9 weeks Test Review

Newton's Third Law of Motion states that for every action, there is an equal and opposite reaction. Which of the following is an example of this law?

• A car accelerating on a highway

• A book resting on a table

• A rocket launching into space

• A ball rolling down a hill

A student is driving her car when an insect strikes her windshield. Which of the following statements best describes the forces in this situation?

• The insect strikes the windshield with a force, and the windshield exerts no force on the insect.

• The insect strikes the windshield with the same force as the windshield strikes the insect.

• The insect exerts no force on the windshield, and the windshield strikes the insect with a large force.

• The insect strikes the windshield with a small force, and the windshield strikes the insect with a large force.

Two students are standing next to each other on a level field. One of the students throws a table tennis ball forward toward a line 2.0 meters away. At the same time, the second student throws a bowling ball in the same direction. Both balls take the same time to travel the 2.0 meters.

• The table tennis ball has more mass than the bowling ball.

• The bowling ball has more mass than the table tennis ball.

• Both balls have the same mass.

• The table tennis ball is thrown with more force than the bowling ball.

Which of the following statements explains why only the second student feels a noticeable backward push?

• The bowling ball undergoes a much larger acceleration.

• The bowling ball exerts a much larger reaction force.

• The bowling ball requires more force to overcome gravity.

• The bowling ball converts more inertia into kinetic energy.

A bottle rocket experiences a 500 N force to the right and 300 N of air resistance to the left. What will happen to the rocket?

• It will accelerate to the left.

• It will accelerate to the right.

• It will not accelerate.

• It will move in a circular path.

A box experiences a 20 N force to the left and a 19 N frictional force to the right. What will happen to the box?

• It will accelerate to the left.

• It will accelerate to the right.

• It will not accelerate.

• It will move upwards.

A rope experiences three 400 N forces to the left and three different 410 N forces to the right. What will happen to the rope?

• It will accelerate to the left.

• It will accelerate to the right.

• It will not accelerate.

• It will move downwards.

A box experiences a 20 N force to the left and two different 8 N forces to the right. What will happen to the box?

• It will accelerate to the left.

• It will accelerate to the right.

• It will not accelerate.

• It will move in a circular path.

A skateboard is pushed up a hill with a 90 N force to the left and experiences a gravitational force of 100 N to the right. What will happen to the skateboard?

• It will accelerate to the left.

• It will accelerate to the right.

• It will not accelerate.

• It will move downwards.

A car experiences a 300 N force to the right from the engine and separate 150 N force due to air resistance to the left. What will happen to the car?

• It will accelerate to the left.

• It will accelerate to the right.

• It will not accelerate.

• It will move upwards.