Question

A motor car of mass 1200kg is moving along a straight line with a uniform velocity of 90km/hr in 4 seconds by an external unbalanced force .calculate the change in momentum and the magnitude of force

Answer 1

u=90 km/h =25 m/s  

V=18 km/h=5 m/s

as v-u÷t =a

= -5 m/s^-2

change I momentum

mu - mv = 1200×5 -1200×25=-24000 kg/m/s

force=ma

1200×-5= -6000(negative sign represents regarding force)

hope this answer will help you.