A particle located at the position vector m has a force N acting on it. The torque about the origin is

Complete question:

A particle located at the position vector r = (i + j) m has a force F = (2i + 3j) N acting on it. The torque about the origin is

The torque about the origin is (5k) N.m

Explanation:

The torque about the origin is the vector or cross product of the two vectors.

τ = r x F (N.m)

Where;

τ is the torque about the origin

τ = r x F

τ = (i + j) x (2i + 3j)

For cross product;

i x j = k

i x k = j

j x k = i

i x i = 0

j x j = 0

k x k = 0

τ = (i + j) x (2i + 3j)

τ = (i x 2i) + (i x 3j) + (j x 2i) + (j x 3j)

τ = (0) + (3k)+ (2k) + 0

τ = (5k) N.m

Therefore, the torque about the origin is (5k) N.m