JEE Main202225 Jun 2022Morning ShiftPhysicsRotational MotionActual
If force F → = 3 i ^ + 4 j ^ - 2 k ^ acts on a particle having position vector 2 i ^ + j ^ + 2 k ^ then, the torque about the origin will be:
Options
- A- 10 i ^ + 10 j ^ + 5 k ^
- B3 i ^ + 4 j ^ - 2 k ^
- C10 i ^ + 5 j ^ - 10 k ^
- D10 i ^ + j ^ - 5 k ^
Correct answer
A. - 10 i ^ + 10 j ^ + 5 k ^
Step-by-step solution
Torque in vector form is expressed as vector multiplication of position vector and force. τ → = r → × F → ⇒ τ → = i ^ j ^ k ^ 2 1 2 3 4 - 2 ⇒ τ → = - 2 - 8 i ^ - - 4 - 6 j ^ + 8 - 3 k ^ ⇒ τ → = - 10 i ^ + 10 j ^ + 5 k ^   N   m