Question

Find torque of a force=(7i+3j-5k) about the origin. The force acts on a particle whose position vector is (i-j+k)?

Answer 1

Torque is defined as `vec tau = vec r× vec F` (`vec r` is the position vector and `vec F` is the force vector)

So, here `vec tau =(i-j+k)×(7i+3j-5k) = (2i+12j+10k)`

So, `| vec tau | = sqrt(4+144+100)=sqrt(248)=15.74 N.m`