Question

Force of -F_k acts on O, the origin of the coordinate system. The torque about the point (1, - 1) is

(a)  F(i - j)

(b)  -F(i + j)

(c) F(i + j)

(d)  -F(i + j)

Answer 1

Correct Option (c) F(i + j)

Explanation: 

The torque about the grven position, τ = r x F

Here, r = i - j and F = -Fk

:. τ = (i - j) x (-Fk)

= F[(-i x k) = (j x k)]

=F(j + i) = F(i  j)