physics
posted by Chris .
A cart of mass 340 g moving on a frictionless linear air track at an initial speed of 1.2 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 .66m/s.
a) what is the mass of the second cart?
b)What is its speed after impact?
c)What is the speed of the twocart center of mass?
I know that in an elastic collsion momentum and energy is conserved. What would be the equation i would use for this problem? I can't figure out the equations for a) and b) but I think for
c) would I use V= (m_1* v_1 + m_2 *v_2)/(m1+m2)

The equation for the first part is
V_1Final = [(m_1m_2)/(m_1+m_2)]*V_1Origional
I used conservation of momentum for the second part.