How much work must work be done by a force on 50 kg body in order to accelerate it in the direction of force from rest to `20 ms^(-1)` is 10 s?

Options

A. `10^(-3) J`
B. `10^(4) J`
C. `2xx10^(3) J`
D. `4 xx10^(4) J`

Answer

B

Explanation

As, equation of motion is
`v=u+at implies 20 =0+a xx 10`
`20=a xx10 implies a=2 m//s^(2)`
Now, distance `s=ut+1/2 at^(2)`
`implies s=0+1/2 xx2xx10xx10`
or `s=100 m`
`W=F.s ="mas"=50xx2xx100=10^(4) J`