Question

A motorcar of mass 1500 kg is moving along a straight line with a uniform
velocity of 108 km/h. Its velocity is slowed down to 54 km/h in 5 sec by
applying brakes. Find the total change in its momentum.​

Answer 1

Answer:

Given :

➡️ mass of the motorcar = 1500kg

➡️ initial velocity = u = 108km/hr

That is, u = 108×1000/3600 m/s

u = 30m/s

➡️ final velocity = v = 54km/hr

That is, v = 54×1000/3600 m/s

v = 15m/s

To find :

➡️ Change in momentum.

Solution :

we have

Change in momentum = m(v-u)

That is, change in momentum = 1500(15-30) kg m/s

That is, Change in momentum = 1500×(-15) kg m/s = -7500kg m/s

The change in momentum is 7500kg m/s.