Question

A body of mass 1000 kg moving at a speed of 10m/s reaches the speed of 50m/s in 20s . calculate the force required to do so

Answer 1

mass m =1000kg
initial velocity u =10m/s
final velocity V =50m/s
time t =20s
force F =rate of change of momentum
F=m(v-u)/t
F=1000(50-10)/20
F=1000x40/20
F=2000N.

Answer 2

distance = speed / time
distance = 50/10/20
distance = 5/20
distance = 4 m
velocity = displacement(distance)/time
= 4 / 20
velocity = 5 m/s. Here u = 0
v = u + at
5 = 0 + a × 20
a = 0+5/20
a = 5/20
a = 4m/s.

force = mass × acceleration
f = 1000 × 4
f = 4000 N