Question

State the work done in the following situations:

A person carrying bricks on his head on a level road from one place to another.

Answer 1

1. If force and displacement are acting in the same direction then the work done on the object is positive, and if they are in opposite direction then it is negative work done. If force and displacement become perpendicular to one another then it is zero work.
2. When a person lifts the brick from the ground and places it on its head, then work is done, since displacement is caused by the force applied.
3. But when he is carrying the brick by placing it on his head, on a level road, the displacement is not in direction of the force applied.
4. The force and displacement are at right angles.

Hence, the work done is equal to zero.