Question

A force of –F$\hat{k}$ acts on O, the origin of the coordinate system. The torque about the point (1, –1) is
(a) $F(\hat{i}-\hat{j})$
(b) ) $-F(\hat{i}+\hat{j})$
(c) ) $F(\hat{i}+\hat{j})$
(d) ) $-F(\hat{i}-\hat{j})$

Answer 1

Answer:

C) F(i^+  j^)

Explanation:

We will determine the displacement vector with respect to the origin. next we will cross product the displacement vector along with the force vector to determine the torque produced by given force about a desired point.

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

Where, r = i^ - j^ and F = -Fk (Given)

Thus, τ = (i^ - j^) x (-Fk)

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

=F(j^ + i^)

= F(i^+  j^)

Thus, the torque about the point (1,−1)is F(i^+  j^)