A bullet of mass 0.04 kg moving with a speed of 90 m/s enters a heavy wooden block and is stopped af

Question

A bullet of mass 0.04 kg moving with a speed of 90 m/s enters a heavy wooden block and is stopped after a distance of 60 cm. What is the average resistive force exerted by the block on the bullet?

Professor PC Thomas Classes · Answer

Retardation is $a = \frac{v^2 - u^2}{2s} = \frac{0 - 90^2}{2 	imes 0.6} = -6750$ m/s². Retarding force is $F = ma = 0.04 	imes 6750 = 270$ N.