Question

You are playing ice hockey with friends on a frozen pond. The hockey puck (mass 0.2 kg) is sliding on the ice at 10 m/s when it starts to hail. A hailstone lands on the puck, causing it to slow to 8 m/s. What mass does the hailstone have

Answer 1

The mass of the hailstone is
`m_2 = 0.05`

Step-by-step explanation:

From the question we are told that

The mass of the hockey puck is
`m_1 = 0.2 \ kg`

The initial speed of the puck is
`u_1 = 10 \ m/s`

The final speed of the puck is
`v_f = 8 \ m/s`

According to the principles of linear momentum

`m_1u_1 + m_2u_2 = (m_1 + m_2)v_f`

At initial the velocity of the hailstone was zero so

`u_2 = 0 \ m/s`

So

`m_1 u_1 = (m_1 + m_2 )v_f`

substituting values

`0.2 * 10 = (0.2 + m_2 )* 8`

=>
`2 = (0.2 + m_2 )* 8`

=>
`0.25 = 0.2 + m_2`

=>
`m_2 = 0.05`