Two hockey pucks with mass 0.1 kg slide across the ice and collide. Before the collision, puck 1 is going 8 m/s to the east and puck 2 is going 7 m/s to the west. After the collision, puck 1 is going 7 m/s to the west. What is the velocity of puck 2?

Answer:Velocity 8 m/sExplanation:Given:m₁ = m₂  = 0.1 kgv₁ = 8 m/sv₂ = - 7 m/sv₁' = - 7 m/s ____________v₂' - ?Law of conservation of momentum:m₁·v₁ + m₂·v₂ = m₁·v₁' + m₂·v₂'m₁·8 - m₂·7 = - m₁·7 + m₂·v₂'m₁ = m₂8 - 7 = - 7 + v₂'v₂' = 8 m/s = v₁ This phenomenon is called "velocity exchange".