Question

A body of mass m was slowly hauled up the hill as shown in the fig. by a force F which at each point was directed along a tangent to the trajectory. Find the work performed by this force, if the height of the hill is h, the length of its base is I and the coefficient ot friction is `mu`.
.
A. `mgl`
B. `-mgl`
C. `mgh`
D. zero

Answer 1

Correct Answer - C
`Sigma W_("net") = - Delta K`
As partical is moving sloely, this means `delta K = 0`
`W_(N) + W_(F) + W_(mg) = Delta K`
But `W_(N) = 0 as vec N _|_ d vecr`
`0 + W_(F) - mgh = 0`
`W_(F) - mgh`