Consider the situation - A laborer carrying bricks on his head on a level road from one place to another. Find the work done in the process (a) by gravity, (b) by man (c) by frictional force between man and ground.

A coolie carries a load of 50 kg on his head and walks on a level road upto 100m. What is the work done by him?

A man carries a load on his head through a distance of 5 m. The maximum amount of work is done when he

A man carries a load of 5 kg on his head through a distance of 10 m. the minimum amount of work is done when he

In the figure shown, a solid sphere of mass 'm' and radius r is released from a height 6r to slide down a smooth surface. A plank of same mass 'm' touches the horizontal portion of the surface at the ground. The co-efficient of friction between the plank and the sphere is mu and that between the plank and the ground is mu//4 . Find the work done by the friction force between the plank and the ground till the sphere starts pure rolling on the plank. Neglect the height of the plank.

A man of mass M jumps from rest, straight up, from a flat concrete surface. Centre of mass of the man rises a distance h at the highest point of the motion. Find the work done by the normal contact force (between the man’s feet and the concrete floor) on the man.

In the electric field of charge Q, another charge is carried from A to B, A to C, A to D and A to E, then work done will be :

Consider the situation of figure . The work done in taking a point charge form P to A is W_A from P to B is W_B from P to C is W_C.

Assertion : Work done by or against gravitational force in moving a body from one point to another is independent of the actual path followed between the two points. Reason : This is because gravitational forces are conservative forces.

A woman lifts a box weighing 40N from the floor to a shelf 1.5 m above. (a) find the work done by the force (F) the woman exerts on the box (b) Find the work done on the box by its own weight (w) (c ) Find the net work done on the box.

A man of mass 80kg pushes box of mass 20kg horizontaly. The man moves the box with a constant acceleration of 2 m//s^(2) but his foot does not slip on the ground. There is no friction between the box and the ground. There is no friction between the box and the ground. whereas there is sufficient friction between the man's foot and the ground to prevent him from slipping. Assertion:- The force applied by the man on the box is equal and opposite to the force applied by the force applid by the box on the man. Reason:- Friction force applied by the ground on the man is 200N.