Question

a 300 g mass moving at 7.5 cm/s eastward collides with a 500 g mass moving at 5.0 cm/s westward on a horizontal low friction surface. The two masses stick together after the collision. What are the velocities of each mass after the collision?

Answer 1

This is an inelastic collision, and using the conservation of momentum equation:
\[m_1u_1 + m_2u_2 = (m_1+m_2)v\]
since they "stick together" they are considered as a whole new particle with their own respective velocity, where "u_1" and "u_2" are their respective initial velocity and "v" is the velocity of the whole new particle after the inelastic collision. You can plug in your values from here and remember to assign a positive direction and negative direction since one's moving west and the other is moving east before the collision.