Q. A particle of mass 1 kg is projected with an initial velocity 10 ${ms}^{- 1}$ at an angle of projection $45^{0}$ with the horizontal. The average torque acting on the projectile, between the time at which it is projected and the time at which it strikes the ground, about the point of projection in newton-metre is
A) 25
B) 50
C) 75
D) 100
Explanation
(b) $\tau = \frac{dL}{dt} = m(u^{2}\cos^{2}{\theta) = (1)(10)^{2}\cos^{2}{45{^\circ} = 50\ }}$ Nm
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.