Question

Confused on how to find the mass of player 2.

Two hockey players are traveling at velocities of v1 = 13 m/s and v2 = -17 m/s when they undergo a head-on collision. After the collision, they grab each other and slide away together with a velocity of -3.5 m/s. Hockey player 1 has a mass of 122 kg. What is the mass of the other player?

thank you.

Answer 1

here in this type of collision we can use momentum conservation

`P_(1i) + P_(2i) = P_(1f) + P_(2f)`

here we know that

`m_1 = 122 kg`

`v_(1i) = 13 m/s`

`v_(2i) = -17 m/s`

`v_(1f) = v_(2f) = - 3.5 m/s`

now by above equation of momentum conservation

`122* 13 + m_2*(-17) = 122*(-3.5) + m_2*(-3.5)`

`1586  - 17*m_2 = - 427 - 3.5* m_2`

`1586 + 427 = (17 - 3.5)*m_2`

`2013 = 13.5*m_2`

`m_2 = (2013)/(13.5)`

`m_2 = 149 kg`

so mass of the player 2 will be approx 149 kg