Question

which chair(s) experienced the strongest force when hit? how do you know?
a the blue and red chairs experienced the strongest force because they are both more massive than the yellow chair and they changed speed by the same amount.
b the red chair experienced the strongest force because it is as massive as the blue chair and has the highest ending speed.
c all three chairs experienced the same force because they changed speed by the same amount.
d the blue chair experienced the strongest force because it takes more force to slow an object than it takes to make it go faster.

Explanation:

According to Newton's second - law of motion $F = ma$ (force equals mass times acceleration). If the change in speed (acceleration) is the same, the object with greater mass will experience a greater force. Option a correctly relates mass and force when the change in speed is the same. Option b wrongly assumes that ending speed alone determines force without considering acceleration and mass relationship properly. Option c ignores the mass differences. Option d has no basis as force to slow or speed up an object depends on mass and acceleration, not on the direction of speed change.

Answer:

A. The blue and red chairs experienced the strongest force because they are both more massive than the yellow chair and they changed speed by the same amount.