A body of mass 2.9 kg is suspended froth a string of length 2.5m and is at rest. A bullet of mass 100 g, moving horizontally with a speed of 150ms−1 , strikes and sticks to it. What with the maximum angle made by the string with the vertical after the impact? (g=10ms−2)

By Law of Conservation of Momentum 2.9(0)+0.1(150)=(2.9+0.1)v ⇒v=(0.1)(150)3 ⇒v=5 ms−1 By Law of Conservation of Energy (Loss in K.E. ofcombined system)=(Gain in P.E. of combined system) ⇒12(M+m)v2=(M+m)gh ⇒v2=2gh But h=ℓ(1−cosθ) ⇒v2=2g(1−cosθ) ⇒25=2(10)(2.5)(1−cosθ) ⇒cosθ=12 ⇒θ=600