A cart with mass 340 g moving on a frictionless linear air track at an initial speed of 1.5 m/s undergoes an elastic collision with an initially stationary cart of unknown mass. After the collision, the first cart continues in its original direction at 0.42 m/s.

Question

(a) What is the mass of the second cart? ___ g

(b) What is its speed after impact?
_____ m/s

(c) What is the speed of the two-cart center of mass? _____ m/s

Answer 1

The equation for the first part is

V_1Final = [(m_1-m_2)/(m_1+m_2)]*V_1Origional

I used conservation of momentum for the second part

Use

V = (m_1*v_1 + m_2*v_2)/(m_1+m_2)

for part c. I am not sure if you should use v original or finial for the velocities in the equation.

Answer 2

You would use the final velocities.