Question

Two soccer players run toward each other. One player has a mass of 85 kg

and runs west with a speed of 8 m/s, while the other has a mass of 105 kg
and runs east with a speed of 7 m/s. What is the total momentum of the
system made up of the two players?

Answer 1

p = 55 kg * m/s east

Step-by-step explanation:

The answer above explains it neatly, but leaves the direction out of the answer. The player heading east has more momentum, so the net momentum of the system is east.

Answer 2

Total momentum, p = 55 kg-m/s

It is given that,

Mass of player 1, m₁ = 85 kg

Mass of player 2, m₂ = 105 kg

Speed of player 1, v₁ = -8 m/s (west)

Speed of player 2, v₂ = 7 m/s (east)

Momentum is equal to the product of mass and velocity. For this system, momentum is given by :

p=m_1v_1+m_2v_2p=m

1

v

1

+m

2

v

2

p=85\ kg\times (-8\ m/s)+105\ kg\times 7\ m/sp=85 kg×(−8 m/s)+105 kg×7 m/s

p = 55 kg-m/s

The total momentum of the system made up of the two players is 55 kg-m/s.