Question

A particle of mass $1kg$ is projected with an initial velocity $10m{s}^{-1}$ 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 $Nm$ is:

• A. $25$
• B. $50$
• C. $75$
• D. $100$

Answer 1

The correct option is B $50$

Range of projectile $R=\frac{u^2\sin 2\theta }{g}=\frac{(10{)}^2}{10}=10m$
Average Torque $\tau =mg\times \frac{R}{2}=1\times 10\times \frac{10}{2}=50Nm$