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valentina_108 [34]
3 years ago
9

A moving freight car collides with an identical one that is at rest. If momentum is conserved, what happens to the second car af

ter the collision? It attains the same speed as the first car. It moves at half the speed of the first car. It moves at twice the speed of the first car.
Physics
1 answer:
yKpoI14uk [10]3 years ago
4 0

For all elastic collisions we have

e = \frac{v_2 - v_1}{u_1 - u_2}

e = 1 = \frac{v_2 - v_1}{u_1 - u_2}

v_2 - v_1 = u - 0

also by momentum conservation we will have

m_1 u_1 + m_2 u_2 = m_1 v_1 + m_2 v_2

since two cars are identical so we know that

m_1 = m_2 = m

u + 0 = v_1 + v_2

now by solving two equations we will have

v_2 = u

v_1 = 0

so the correct answer must be

It attains the same speed as the first car.

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