A point of application of a force F→=4i^−5j^+3k^  is moved from r→0=i^+2j^+3k^ . The torque about a point r→=3i^−2j^−3k^  is:

Torque acting about a point P [ Position vector of point P is P→ (say)] due to force F→  is given byτ→=P→×F→P→=r→0−r→=(i^+2j^+3k^)−(3i^−2j^−3k^)=−2i^+4j^+6k^τ→=(−2i^+4j^+6k^)×(4i^−5j^+3k^)=i^(12+30)−j^(−6−24)+k^(10−16)=42i^+30j^−6k^