Work is done when a load is lifted, when we lift our body above the ground, when we climb stairs, throw a ball into the air or even when we open a door or crack a nut.
In our daily life, we used the world `work’ very frequent and it means some job. But in science it has a specific meaning. When force is used on an object and it moves through a distance, we say that work is done.
Force (Photo credit: pizzodisevo)
When a man lifts a weight to a certain height from the ground, the muscular force which he exerts does work against the force of gravity. Work is done when a load is lifted, when we lift our body above the ground, when we climb stairs, throw a ball into the air or even when we open a door or crack a nut. So in simple words, when force is applied on body to make it move trough a distance, against the force of gravity, works is done.
Tidal force as appearance of Gravity force (Photo credit: Wikipedia)
Work always involves overcoming some opposing forces.
Secondly, when we push some heavy object like a box, we work against the frictional force. So the resistance is either against the force of gravity or the frictional force.
It is important to consider how work is measured. When a body is lifted from the ground, work, as we have said above, is done against the force of gravity, and the amount of work done will depend on the height through which the body is raised. We are therefore concerned with force and the distance through which it acts.
Thus measurement of work involves the units of force and distance. In other words, the work done is proportional to both the applied force and the distance through which the force acts. Therefore- work= force x distance.