Puck 1 (0.5 kg) travels with velocity 20 m/s to the right when it collides with puck 2 (2 kg) which is initially at rest. After the collision, puck 1 moves with a velocity of - 4 m/s. Assume that no external forces are present and therefore the momentum for the system of pucks is conserved. What is the final velocity (in m/s) of puck 2 after the collision

The final velocity of puck 2 is 6 m/s to the right

Explanation:

Given;

mass of puck 1, m₁ = 0.5 kg

mass of puck 2, m₂ = 2 kg

initial velocity of puck 1, u₁ = 20 m/s

initial velocity of puck 1, u₂ = 0

final velocity of puck 1, v₁ = - 4 m/s

Let the final velocity of puck 2 = v₂

Applying the principle of conservation linear momentum, total momentum before collision is equal to total momentum after collision.

m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂

(0.5 x 20) + (2 x 0) = (0.5 x - 4) + 2v₂

10 = - 2 + 2v₂

2v₂ = 12

v₂ = 12/2

v₂ = 6 m/s

This positive final velocity of puck 2, indicates that it moved to the right.