A 110 kg football player running with a velocity of 5.0 m/s hits another stationary football
player who has a mass of 90 kg. Upon impact, the first player immediately stops, thus propelling
the second player backwards. What is the final velocity of the second player?

Respuesta :

Answer:

The final velocity of the second player is 6.1 m/s.

Explanation:

The final velocity of the second player can be calculated by conservation of linear momentum (p):

[tex] p_{i} = p_{f} [/tex]  

[tex] m_{a}v_{a_{i}} + m_{b}v_{b_{i}} = m_{a}v_{a_{f}} + m_{b}v_{b_{f}} [/tex]  (1)

Where:

[tex]m_{a}[/tex]: is the mass of the first football player = 110 kg

[tex]m_{b}[/tex]: is the mass of the second football player = 90 kg

[tex]v_{a_{i}}[/tex]: is the initial velocity of the first football player = 5.0 m/s

[tex]v_{b_{i}}[/tex]: is the initial velocity of the second football player = 0 (he is at rest)

[tex]v_{a_{f}}[/tex]: is the final velocity of the first football player = 0 (he stops after the impact)

[tex]v_{b_{f}}[/tex]: is the final velocity of the second football player =?

By solving equation (1) for [tex]v_{b_{f}}[/tex] we have:

[tex] 110 kg*5.0 m/s + 0 = 0 + 90 kg*v_{b_{f}} [/tex]

[tex] v_{b_{f}} = \frac{110 kg*5.0 m/s}{90 kg} = 6.1 m/s [/tex]

Therefore, the final velocity of the second player is 6.1 m/s.

I hope it helps you!