Question

Students perform an experiment in which they drop two eggs with equal mass from a balcony. In the first trial, the egg hits the ground and breaks. In the second trial, the egg hits a foam cushion and does not break or bounce.

What conclusions about impulse can the students make?

The impulse was greater in the first experiment because the egg broke.
The impulse was greater in the second experiment because the egg did not break.
The impulse was the same in both experiments because the egg came to a stop.
The impulse cannot be determined without the mass and velocity of the eggs.

Answer 1

The impulse was the same in both experiments because the egg came to a stop.

Reason: impulse = change in momentum = m(vf − vi). Both eggs have the same mass and the same initial speed, and in both cases vf = 0, so the magnitude of the impulse is the same. (What differs is the force-time profile: the hard ground produces a larger peak force over a shorter time, which can break the egg, while the foam gives a smaller force over a longer time.)