Question

is work done if body roates in circular path or is it possible that a force acts on a body still the work done is zero? Explain with an example.

Answer 1

if force acting on a body then Workdone can be zero
This when an object is at rest and no external force except gravity is acting on it in this case the work that would be zero as the force acting on it is perpendicular. Therefore the displacement is zero and if displacement is zero work done would be automatically 0.

Mathematically

W = fs

Is s = displacement is 0

Work = 0

If there is uniform circular motion then only the Workdone will be zero this is because in uniform circular motion net force acting on particle is always perpendicular to instentanious velocity so f.ds is always zero
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Answer 2

$\huge\green{HELLO THERE !}$

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$\huge\blue{FIRST CASE}$

When IS WORK DONE WHEN BODY IS ROTATING IN CIRCULAR PATH ?

We know that in circular path initial and final points are same

So .....

Displacement in circular path is zero because diaplacement is ahortest possible distance between initial and final point and her initial and final points are same so displacement is zero

Now ....

W=Fd

as d = 0 in circle

So.......

W = F(0)

W = 0

We came to a conclution that no work is done in circular path

$\huge\pink{SECOND CASE}$

A FORCE IS APPLIED ON A BODY BUT STILL WORK DONE IS ZERO

We know that

W =F.d

W=Fd cos theta

Now if angle between force and displacement is 90° then

cos 90° = 0

Therefore work done will be :-

W = Fdcos (90)

W = Fd (0)

W = 0

SO THIS IS THE CASE WHERE FORCE IS APPLIED BUT STILL WORK DONE IS ZERO

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$\huge\orange{INSHALLAH IT WILL HELP U }$