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Each croquet ball in a set has a mass of 0.50 kg. the green ball travels at 10.5 m/s and strikes a stationary red ball. if the green ball stops moving, what is the final speed of the red ball after the collision?

Respuesta :

mathssydney
Momentum conservation law!
mv before collision = mv after collision
momentum of green ball before collision 0.5 kg * 10.5 m/s + momentum of red ball before collision 0.5 kg * 0 m/s = momentum of green ball  after collision 0.5 kg * 0  m/s + momentum of red ball before collision 0.5 kg *  unknown speed in m/s
0.5*10.5 + 0.5*0 = 0.5*0 + 0.5*v
v = 10.5 m/s

Explanation:

It is given that,

Mass of both green and red ball, m₁ = m₂ = 0.5 kg

Initial speed of green ball, u₁ = 10.5 m/s

Initial speed of red ball, u₂ = 0 ( rest )

Final speed of green ball, v₁ = 0 (it stops)

We need to find the final speed of the red ball after the collision. Lt it is equal to v₂. Using the conservation of momentum as :

[tex]m_1u_1+m_2u_2=m_1v_1+m_2v_2[/tex]

[tex]m_1u_1+0=0+m_2v_2[/tex]

[tex]v_2=\dfrac{m_1u_1}{m_2}[/tex]

Since, m₁ = m₂

[tex]v_2=u_1[/tex]

So, the final speed of red ball after the collision is 10.5 m/s. Hence, this is the required solution.                                      

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