Question

A bullet of mass 5 gm is fired from a gun of mass 5 kg. What is the velocity of the bullet if the recoil velocity is 500 m/s

Answer 1

Answer:

conservation of moventum

pi = pf

0 = pf

mv =Mu

5x500= 5xu

500 = u

Answer 2

Given :

Mass of the bullet = 5 g = 0.005 kg

Mass of the gun = 5 kg

Recoil velocity of the bullet = 500 m/s

To Find :

Velocity at which bullet is fired.

Solution :

❖ Since no external force acts on the whole system, linear momentum is conserved.

• We know that it is measured as the product of mass and velocity.

Initial momentum of the system will be zero. (i.e., at rest)

$\tt:\implies\:0=p_1+p_2$

$\sf:\implies\:0=m_1v_1+m_2v_2$

» m₁ denotes mass of the gun

» v₁ denotes recoil velocity

» m₂ denotes mass of the bullet

» v₂ denotes velocity of the bullet

By substituting the given values;

$\tt:\implies\:0=(5)(500)+(0.005)v_2$

$\tt:\implies\:-0.005v_2=2500$

$\tt:\implies\:v_2=-\dfrac{2500}{0.005}$

$\sf:\implies\:\underline{\boxed{\bf{\orange{v_2=-500,000\:mps=-500\:kmph}}}}$

[Negative sign shows opposite direction.]