Question

A particle at opposition r=I+ 2j+ 3k is acted upon by a force F 2= 4i +5j +6k.

Evaluate the torque experienced by the particle.

Answer 1

The torque experienced by the particle

$$\vec \tau=\vec r\times \vec F$$

Hence

$$\vec \tau=(\hat i+ 2\hat j+ 3\hat k)\times (4\hat i +5\hat j +6\hat k)\\ =5\hat k-6\hat j-8\hat k+12 \hat i+12 \hat j-15 \hat i\\ =-3\hat i+6\hat j-3\hat k$$