Question

A bullet of mass 20 g has an initial speed of 1 ms⁻¹ just before it starts penetrating a mud wall of thickness 20 cm. If the wall offers a mean resistances of 2.5 10⁻² N, the speed of the bullet after emerging from the other side of the wall is close to
(A) 0.7 ms⁻¹ (B) 0.3 ms⁻¹
(C) 0.1 ms⁻¹ (D) 0.4 ms⁻¹

Answer 1

m=20g,u=1m/s,v=?

S=20×10−2m

a=20×10−3−2.5×10−2m/s2

v2=u2+2as

v2=1−2×20×10−32.5×10−2×10020

v=21≃0.7m/s