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The torque of force vec(F)=-3hat(i)+hat(...

The torque of force `vec(F)=-3hat(i)+hat(j)+5hat(k)` acting at the point `vec(r)=7hat(i)+3hat(j)+hat(k)` is ______________?

A

`14 hat(i) - 38 hat(j) + 16hat(k)`

B

`4hat(i) + 4hat(j) + 6hat(k)`

C

`21 hat(i) + 4hat(j) + 4hat(k)`

D

`-14 hat(i) + 34hat(j) - 16hat(k)`

Text Solution

Verified by Experts

The correct Answer is:
A
`vec(tau)= vec(r) xx vec(F) = (7 hat(i) + 3hat(j) + hat(k)) (-3hat(i) + hat(j) + 5hat(k))`
`vec(tau)= |(hat(i),hat(j),hat(k)),(7,3,1),(-3,1,5)|= 14 hat(i)- 38 hat(j) + 16hat(k)`
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