Determining velocity of objects after collision

[sikrut]

"A projectile of mass m1 moving with speed v1 in the -x direction strikes a stationary target of mass m2 head-on. The collision is elastic. Use the Momentum Principle and the Energy Principle to determine the final velocities of the projectile and target, making no approximations concerning the masses. "


All I've gotten so far is that:

P_1f + P_2f = P_1i + P_2i

but v_2i = 0 SO P_2i = 0

am I on the right track? I'm pretty much lost at this point.

 

[ehild]

All I've gotten so far is that:

P_1f + P_2f = P_1i + P_2i

but v_2i = 0 SO P_2i = 0

am I on the right track?

Yes, P_2i = 0, go ahead. You have also conservation of energy.

ehild