Question

Two hockey pucks, each 0.1 kg, slide across the ice and collide. Before the collision, 1 puck is moving 13m/s to the east and puck 2 is moving 18m/s to the west. After the collision, puck 1 is moving at 18m/s to the west. What is the velocity of puck 2.

Answer 1

13 m/s east

Step-by-step explanation:

got it right.

Answer 2

Using conservation of momentum:

`\begin{gathered} p1=p2 \\ p1=m1u1+m2v1 \\ p2=m1u2+m2v2 \end{gathered}`

Where:

m1 = mass of the hockey puck 1 = m2 = mass of the hockey puck 2 = 0.1kg

u1 = Initial speed of the hockey puck 1 = 13m/s

u2 = Final speed of the hockey puck 1 = 18m/s

v1 = Initial speed of the hockey puck 2 = 18m/s

v2 = Final speed of the hockey puck 2

Therefore:

`\begin{gathered} 0.1(13)+0.1(18)=0.1(18)+0.1v2 \\ 13+18=18+v2 \\ solve_{\text{ }}for_{\text{ }}v2: \\ v2=13+18-18 \\ v2=13m/s \end{gathered}`

Answer:

13 m/s