Question

Why is it tiring to push hard against a solid wall even though you are doing no work?

Short answer

It is tiring to push hard against a solid wall because although there is no displacement by pushing it, you keep applying a muscular force, thereby exhausting your energy.

Step-by-step solution

Determination of work done

The amount of work done can be obtained by the product of the magnitude of the force applied to an object and the object's displacement due to the force's application in the direction of the force.

Now, let us understand why it is tiring to push hard against a solid wall

No work is done on the wall because a person’s muscular force cannot displace a solid wall. It is very tiring to push the wall because in order to make a displacement, you keep increasing the force and exhaust a good amount of energy in the process.

It has to do with the process of working muscle. Muscles are basically the collection of filaments, and these can either slow down or contract during muscular activity. Each filament cannot maintain a constant force. In order to apply a constant force of larger magnitude, the filaments are contracting or slowing down at regular intervals.

Hence, at the microscopic level, your muscles are doing work; although you are doing no work with respect to the wall. Thus, it is tiring to push hard against a solid wall.