Question

A bullet of mass 10 gram is fired with an initial velocity of 20 metre per second from a rifle of mass 4kg. Calculate the initial recoil of the rifle?

Answer 1

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Using conservation of linear momentum,

Total initial momentum = Total final momentum

m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂

V = -mv/M    

where, V is recoil velocity

            m is mass of bullet

            v is velocity of bullet

            M is the mass of gun

m = 10g = 10×10⁻³ kg = 10⁻² kg

M = 4 kg

v = 20 m/s

V = ?

V = -10⁻² × 20/4

V = 1/2 × 10⁻¹

V = 0.5 × 10⁻¹

V = 0.05 m/s

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