A heavy rock and a light rock in free fall have the same acceleration. Both rocks have the same acceleration because
A)force due to gravity is the same on each.
B)air resistance is always zero in free fall.
C)inertia of each is the same.
D)ratio of force to mass is the same.
E)none of the above

Question

Quizplus · Accepted Answer

In free fall, the force acting on both rocks is gravity, which is proportional to their mass. However, since gravitational force is divided by the mass to obtain acceleration, the ratio of force to mass (i.e. weight per unit mass) is the same for both rocks. Therefore, they experience the same acceleration.

A Heavy Rock and a Light Rock in Free Fall