CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

In each of the following a force, F is acting on an object of mass, m. The direction of displacement is from west to east shown by the longer arrow. Observe the diagrams carefully and state whether the work done by the force is negative, positive or zero.

Open in App
Solution

Step 1: Formula for work done

Work done on a body is given as,

W = (F cos θ) d

Where, W is the work done by the force.

F is the force, d is the displacement caused due to the force

θ is the angle between the force and the displacement

Step 2: Determine work done for the first case

The direction of force acting on the block to the displacement.

W=F×cosθ×d

Here θ=90°.

W=F×cos90°×d

W=0 cos90°=0

Step 3: Determine work done in the second case

The direction of the force on the block is in the direction of displacement.

W=F×cosθ×d

The angle between the force and displacement is 0°.

W=F×cos0°×d

W=F×d cos0°=1

Step 4: Determine work done in the third case

The direction of force on the block is opposite to the direction of displacement.

W=F×cosθ×d

Here θ=180°.

W=F×cos180°×d

W=F×d cos180°=-1

Hence, the work done in the first case is zero,

The work done in the second case is positive.

The work done in the third case is negative.


flag
Suggest Corrections
thumbs-up
35
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Work Done
PHYSICS
Watch in App
Join BYJU'S Learning Program
CrossIcon