Question

A body of mass 10 kg is moving with a velocity of 20 m/s . A force is applied to it so that in 30s it attains a velocity of 40m/s calculate the value of the force applied.​

Answer 1

Answer:

Work = f × s = m × a × s ( f = m×a)

a = ( v - u)/t = (50 - 40)/2 = 5 m/s

s = (v2 - u2)/2a = 50×50 -40×40/10 =2500-1600/10 = 90m

s = 90 m , a = 5 m/s and Given, m = 20kg

Work = m × a × s

work = 20 × 5 × 90

work = 9000 joul

work = 9kj.

Answer 2

given,

u=20 m/s v=40 m/s

m=10 kg t=30 s

we know

v-u= at

i.e

40-20 = a ×30

20÷30=a

2÷3=a (acceleration)

Now,

F=ma

F= 10 × 2÷3

F =20÷3

F=6.67 N (approx)

thanks ☺