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A slab is subjected to two forces vec F(...

A slab is subjected to two forces `vec F_(1) and vec F_(2)` of same magnitude F as shown in the figure . Force `vec F_(2)` is in XY-plane while force `F_(1)` acts along z-axis at the point `(2 vec I + 3 vec j)` .The moment of these forces about point O will be :

A

`(3hati + 2hatj - 3hatk)`F

B

`(3hati - 2hatj - 3hatk)F`

C

`(3hati + 2hatj + 3hatk)F`

D

`(3hati - 2hatj + 3hatk)F`

Text Solution

Verified by Experts

The correct Answer is:
D
`vectau_(1) = (2hati + 3hatj) xx (hatk)F =(-2hatj + 3hati)F`
`vectau_(2) = (6hatj) xx (F/2)(-hati) = 3Fhatk`
So, `vectau=(3hati - 2hatj + 3hatk)F`
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