Question

A body of mass M was slowly hauled up a rough hill by a force F which at each point was directed along a tangent to the hill. Work done by the force.

• A. Is independent of the shape of trajectory
• B. Depends upon the vertical component of displacement but is independent of horizontal component
• C. Depends upon both the component
• D. Does not depend upon the coefficient of friction.

Answer 1

Answer: (A), (C)

Depends upon both the component
Is independent of the shape of trajectory

Here, the frictional force is always acting tangential to the path and opposing the force. In the support of gravity. So, net work done by the force will be the sum of the works done by friction and gravity.

$W_F=W_g+W_f$

$W_F=mgh+\mu mgx$

Where,

$X$ is horizontal distance covered and $h$ is height of the incline.