Question

Two lab carts are pushed together with a spring mechanism compressed between them. Upon being released, the 5.0-kg cart repels with a velocity of 0.12 m/s in the positive direction, while the 2.0-kg cart goes in the opposite direction. What is the velocity of the 2.0-kg cart?

Answer 1

Answer:

0.3 m/s

Explanation:

Since there's no external force acting on the 2-cart-spring system, the momentum is conserved. And since the total momentum of the 2 carts before the release is 0 (they were at rest), the momentum of cart 1 equals to the momentum of cart 2 post-release.

$m_1v_1 = m_2v_2$

$5*0.12 = 2v_2$

$v_2 = \frac{0.6}{2} = 0.3 m/s$