Question

A man weighing `55kg` supports a body of `20kg` on his head. Calculate work done by him if he moves a distance of `20m(i)` on a horizontal road, (ii) upon a smooth incline of 1 in 5. Take `g=10ms^(-2)`

Answer 1

Here,`m=55+20=75kg, s=20m`
(i) on a horizontal road, `theta=90^(@)`
`W=Fscostheta=Fscos90^(@)=0`
(ii) upon an incline `:sintheta=1//5`
`W=Fcostheta=(mgsintheta)scos0^(@)`
`=75xx10xx(1)/(5)xx20xx1=3000J`