A 50 gram bullet leaves a rifle with a velocity of `400 m//s ` , and the rifle recoils with a velocity of ` 0.5 m//s ` . What is the mass of the rifle

Options

A. 10 kg
B. 20 kg
C. 30 kg
D. 40 kg

Answer

D

Explanation

Here , `m_(1) = 50 g = (50)/(1000) kg = (1)/(20) kg`
`upsilon_(1) = 400 m //s , upsilon_(2) = - 0.5 m// s , m_(2) = ?` From Newton ' s third law of motion ,
`F_(2) = F_(1)` (in magnitude)
`(m_(2) upsilon_(2))/(t)=(m_(1)upsilon_(1))/(t') m_(2) = =(m_(1)upsilon_(1))/(upsilon_(2))=(1)/(20)xx (400)/(0.5)= 40 kg ` .