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Let vecF be the force acting on a partic...

Let `vecF` be the force acting on a particle having position vector `vecrandvectau` be the torque of this force about the origin. Then :

A

`vecr.vectau=0 and vecF.vectau=0`

B

`vecr.vectau=0 and vecF.vectau=0`

C

`vecr.vectaune0 and vecF.vectau=0`

D

`vecr.vectaune0 and vecF.vectaune0`

Text Solution

Verified by Experts

The correct Answer is:
A
Here `vectau=vecFxxvecr`
Now, `vecr.vectau=vecr.(vecFxxvecr)=r(Fr)cos90^(@)`= Zero.
Similarly `vecF.vectau` = zero
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