WORK

WORK Work has different and rather broad meaning in

everyday language. But in physics concept of work has a very clear definition.

The product of the component of a force along the direction of displacement and the magnitude of the displacement is called work.

Consider a constant force F is applied to an object on a horizontal surface. Under this force if the object is displaced by an amount x, parallel to the force, then the work done by the applied force F is defined as the magnitude of the force times the amount of displacement.

W = F.x

F

x

W =(F cos ).θ x

F

x

θ F cos θ

Work is a scalar quantity.

1 Joule is the work done by a force of 1Newton as it acts through a distance of 1metre along the line of force.  1J = 1N.m

P R O B L E M

How much work is done on a vacuum cleaner pulled 3 m by a force of 50 N at an angle of 30˚ above the horizontal?

P R O B L E M

A weight lifter lifts a set of weights a vertical distance of 2.00 m. If a constant net force of 350 N is exerted on the weights, what is the net work done on the weights?

P R O B L E M

If 2.0 J of work is done in raising a 180 g apple, how far is it lifted?