Why is ittiring to hold a heavy weight eventhough no work is done ?

Work Done

Work Done

Four men light a 250 kg box to a height of 1m and hold it without raising or lowering it. (a) How much work is done by the men in lifting the box ? (b) How much work do they do in just holding it ? (c ) why do they get tired while holding it ? (g = 10m//s^2)

Does the work done in moving a body depend on the time in which the work is done ?

Molecular weight of heavy water is

What is the amount of work done by a weight-lifter in holding a weight of 120 kg on his shoulder for 30 s?

A weight lifter jerks 220 kg vertically through 1.5 metre and holds still at that height for two minutes. The work done by him in lifting and in holding it still are respectively

The short sized and heavy weighted sound body persons are called

An automobile jack is used to lift a heavy car by exerting a force that is much smaller in magnitude than the weight of the car. Does this mean that less work is done on the car by the force exerted by the jack than if the car had been lifted directly ? Explain.