Q.

Which of the following are correct expressions for torque acting on a body

A. τ=r×L                               B. τ=ddt(r×p)

C. τ=r×dpdt                            D. τ=Iα

E. τ=r×F

(r = position vector; p = linear momentum; L = angular momentum;

α = angular acceleration; I = moment of inertia; F = force; t = time)

Choose the correct answer from the options given below:          [2025]

1 B, D and E Only  
2 C and D Only  
3 B, CD and E Only  
4 A, B, D and E Only  

Ans.

(3)

τ=r×L                          wrong

τ=ddt(r×p)               correct

τ=r×dpdt=r×F       correct

τ=Iα                                  correct

τ=r×F                            correct