Question

Let a force `vec"F"=-"F"hat"k"` acts on the origin of Cartesian frame of reference. The moment of force about a point (1, -1) will be ______.

विकल्प

• `"F"(hat"i"-hat"j")`

• `"F"(hat"i"+hat"j")`

• `-"F"(hat"i"-hat"j")`

• `-"F"(hat"i"+hat"j")`

Answer 1

Let a force `vec"F"=-"F"hat"k"` acts on the origin of Cartesian frame of reference. The moment of force about a point (1, -1) will be `underline("F"(hat"i"+hat"j"))`.

Explanation:

`"F"=-"F"hat"k"`

P(1, -1)

`vecr=hat"i"-hat"j"`

`vectau=vecrxxvec"F"=abs[[hat"i",hat"j",hat"k"],[1,-1,0],[0,0,-"F"]]="F"vec"i"-hat"j"("-F")="F"(hat"i"+hat"j")`