Question

Find work done , if
Angle between Force
and displacement is 90 degree.

.

Answer 1

Answer: Zero work done.

Explanation:

Let the force imparted on the object be 'F' and displacement occurred, assume = x

So, as work done = force × displacement × cosine of angle between force & displacement,

∴ W = Fs cosθ

=> W = Fs cos90°

=> W = 0 (as cos 90 = 0.)

More:

• Work done is said to be negative when object shows displace on the opposite side of force applied and vice-versa. Ex: Brakes applied on a moving car.
• It is said to be positive when displacement occurs in direction of force. Ex: Walking.
• Zero work done example: Porter/donkey transporting luggage.