A 10 kg box initially at rest moves along a frictionless horizontal surface. A horizontal force to the right is applied to the box. A student calculates the impulse applied by force during the 2 seconds is 4 N. s. and that the impulse applied during the following 3 seconds is 6 Nâs. Required:
a. What, if anything, is wrong with these calculations? If something is wrong, identify it and explain how to correct it. If these calculations are correct, explain why?
b. What is the difference between a perfectly elastic and an inelastic collision?

The answer is below

Explanation:

a) Impulse is the total effect of force which has been acting on a body over a period of time. Impulse is the product of the force and the period of time applied. It is given by:

Impulse = force × time

Given that during 2 seconds, the impulse is 4 Ns, we can calculate the force applied.

Impulse = force × change in time

4 = force * 2

force = 4 / 2 = 2 N.

Hence the impulse applied during the following 3 seconds is:

Impulse = force × change in time = 2 * (2 + 3) = 2 * 5 = 10 Ns

The impulse applied during the following 3 seconds is 10 Ns not 6 Ns

b) In perfectly elastic collision, there is no loss in kinetic energy while in an inelastic collision there is loss in kinetic energy due to energy conversion or transfer.

In perfectly elastic collision the object does not stick together while in an inelastic collision the object stick together.