Question

force and motion end - of - unit assessment (continued)
before
after
crash 1
crash 2

1. scientists created models that show a rocky asteroid crashing into a moon (less mass)

and a planet (more mass). in both crashes, the asteroid was the same mass. scientists
want to know what happened to the asteroid. use the information in the diagram to
answer.
in which crash did the asteroid experience a stronger force? how do you know?
a. crash 2; the force on the planet was stronger in this crash, so the force on the
asteroid was also stronger.
b. there was no force on the asteroid. only the moon and planet experienced a
force in each crash.
c. the diagram doesnt tell you anything about the force on the asteroid. it only
gives information about the force on the planet and the moon.
d. the force was the same in both crashes. the planet and moon changed speed
by the same amount so that means the force on the asteroid was the same in
both crashes

Explanation:

According to Newton's third law of motion, for every action, there is an equal and opposite reaction. In a collision, the force exerted on one object (e.g., the asteroid) has an equal - magnitude force exerted on the other object (e.g., the moon or planet). In Crash 2, the planet (which has more mass) has a stronger force exerted on it (because of its greater mass and the nature of the interaction in a collision - related context, where a more massive object in a collision - like situation where velocities change can imply a stronger force pair). Since the force on the planet is stronger in Crash 2, the force on the asteroid (as the reaction force) is also stronger.

Answer:

a. Crash 2; the force on the planet was stronger in this crash, so the force on the asteroid was also stronger.