Question

A bag of sand of mass m is suspended by rope a bullet of mass (m / 30) is fired at it with a velocity V and gets embedded into it. The velocity of the bag finally is _________ 

(A) (31V / 30) 

(B) (30V / 31) 

(C) (V / 31) 

(D) (V / 30)

Answer 1

Correct option: (C) (V / 31)

Explanation:

m₁ =(m / 30) ; V₁ = V

m₂ = m + (m / 30): V₂ = 2

Principle of conservation of momentum.

m₁V₁ = m₂V₂ 

(m / 30)(V) = {m + (m / 30)}V₂ 

(V / 30) = (31 / 30)V₂ 

V₂ = (V / 31) m/s