WORK, ENERGY AND POWER                                                                GO BACK

Work

Work is defined as the product of force and distance move in the direction of the force

W= F x s

The unit of work is JOULE

One Joule is defined as the Work done when a Force of 1 Newton move through a distance of 1 meter.

Example

A body is pushed on a horizontal surface by a constant force of 20N applied parallel to the surface

What is the work done in moving the body to a distance of 30m ?

What will be the work done if this force is applied to this body in the direction of N30E ?

Solution

W= F x s

W = 20 x 30 = 600j

If the force is applied in the direction N30E

W=Fsin30 x s

=20sin30 x 30 = 300j

Example

A body of mass 50Kg falls from a height of 3m. what is the work Done ? take g=9.8

Force = weight of the body = mass x acceleration due to gravity g

Force = 50 x 9,8 = 490N

Work =F x s = 490 x 3  = 1470joules

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