Question

A 0.40 kg cart is moving at 3 m/s on a frictionless track where it collides with a stationary 0.80 kg cart and two stick together. What is the final velocity of the pair ?

Answer 1

Masses of carts m₁ = 0.4 kg

m₂ = 0.8 kg

Initial Velocities of carts

V₁ = 3 m/s

V₂ = 0 (i.e, it is at rest)

Final velocity of the pair V = ?

From law of conservation of momentum,

m₁ v₁ + m₂ v₂ = (m1 + m2)V

m₁ v₁ + 0 = (m₁ + m₂)V

V = m₁ v₁/m₁ + m₂

= (0.4) (3)/ 0.4 + 0.8 = 1m1s

m₁ v₁ + m₂ v₂ = (m1 + m2)V

m₁ v₁ + 0 = (m₁ + m₂)V

V = m₁ v₁/m₁ + m₂

= (0.4) (3)/ 0.4 + 0.8 = 1m1s

m₁ v₁ + m₂ v₂ = (m1 + m2)V

m₁ v₁ + 0 = (m₁ + m₂)V

V = m₁ v₁/m₁ + m₂

= (0.4) (3)/ 0.4 + 0.8 = 1m1s