Question

a bullet of mass 5g is fired using a gun of 2 kg. the velocity of the bullet is 36km/hr. what is the velocity of the gun?

Answer 1

Conservation of momentum: Initially both gun and bullet are at rest thus momentum P=0
After words momentum = mass bullet * velocity + mass gun*velocity of gun = 0 since momentum is conserved.
Thus mass bullet * velocity of bullet = - mass gun * velocity of gun
velocity of gun = - mass bullet * velocity of bullet / mass gun
v_gun= - 5g*36kg/hr /2000g= -0.09 km/hour
negative sign indicates in opposite direction of bullet

Answer 2

By newton's third law and law of conservation of momentum we can have both the forces balancing
hence
\[5*10^{-3}*(36*5/18)=(2*velocity of gun)\]
velocity of gun=0.025m/s

Answer 3

5 * 35 = 2000 * v

Answer 4

-0.09Km/h