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

Answer:

Total momentum, p = 55 kg-m/s

Explanation:

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 :

$p=m_1v_1+m_2v_2$

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

p = 55 kg-m/s

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

Answer 2

Answer:

+55 kg m/s  

Explanation:

Momentum is the product mass and velocity.

P = m × v

Let the east be in positive direction and west be in negative.

mass of player 1, m = 85 kg

velocity of player 1, v = -8 m/s

mass of player 2, m' = 105 kg

velocity of player 2, v' = +7 m/s

In the absence of any external unbalanced force acting on the system, the total momentum remains conserved. So, the total momentum of this system made having two players is:

P = m v + m' v'

⇒P = (85)(-8) + (105)(7)

⇒P = -680 + 735 = +55 kg m/s