Which of the following is the best example of the third law of motion?

A. A rocket sitting on the ground is preparing for take-off, but it needs an outside force to overcome its inertia of a non-moving object.
Incorrect. This is not example of the third law of motion.

B. A rocket is taking off from earth, which pushes gases in one direction and the rocket in the other.
Correct!

C. A rocket is accelerating through space and exerts a great amount of force because it’s mass and acceleration is so large.
Incorrect. This is not example of the third law of motion.

D. All of the above
Incorrect. Only one of these is an example of the third law of motion.

Newton’s Third Law of Motion is also called —

A. the law of action-reaction
Correct!

B. the law of natural forces
Incorrect. This is not another name for the third law of motion.

C. the law of inertia
Incorrect. This is not another name for the third law of motion.

D. the law of force and acceleration
Incorrect. This is not another name for the third law of motion.

When two equal forces act on the same object in opposite directions, the net force is —

A. greater than either force
Incorrect. If the forces are equal and in the opposite direction, the net force is zero.

B. smaller than either force
Incorrect. If the forces are equal and in the opposite direction, the net force is zero.

C. zero
Correct! If the forces are equal and in the opposite direction, the net force is zero.

D. double the amount of the force
Incorrect. If the forces are equal and in the opposite direction, the net force is zero.

When a soccer ball is kicked, the action and reaction forces do not cancel each other out because —

A. the force of the foot on the ball is bigger than the force of the ball on the foot
Incorrect. According to the third law of motion action-reaction forces are equal.

B. the forces act at different times
Incorrect. The forces are reacting at the same time.

C. the force of the foot on the ball is smaller than the force of the ball on the foot
Incorrect. According to the third law of motion action-reaction forces are equal.

D. the forces are not acting upon the same object
Correct!