Question

From a rifle of mass 4 kg, a bullet of mass 50 g is fired with an initial velocity of 35 m/s. Calculate the initial recoil velocity of the rifle.

Answer 1

$\large{\bf{\gray{\underline{\underline{\orange{Given:}}}}}}$

Mass of rifle = 4kg

Mass of bullet = 50g = 0.05kg

Initial velocity of bullet = 35m/s

$\large{\bf{\gray{\underline{\underline{\green{To\:Find:}}}}}}$

Recoil velocity of rifle.

$\large{\bf{\gray{\underline{\underline{\pink{Solution:}}}}}}$

Recoil velocity of rifle is given by

$\dag\:\boxed{\bf{\purple{V=-\dfrac{mv}{M}}}}$

• M denotes mass of rifle
• m denotes mass of bullet
• v denotes velocity of bullet

$:\implies\sf\:V=-\dfrac{mv}{M}$

$:\implies\sf\:V=-\dfrac{0.05\times 35}{4}$

$:\implies\sf\:V=-\dfrac{1.75}{4}$

$:\implies\bf\:V=-0.437\:ms^{-1}$

[Note : -ve sign shows opposite direction]

Answer 2

Answer:

MgVg=MbVb.

4×Vg=0.05×35.

4Vg=1.75.

Vg=1.75/4

=0.4375 ~ 0.4m/s.