1. The problem statement, all variables and given/known data A 0.24kg object traveling rightward at 3.5m/s collides head-on and elastically with a 0.40kg object traveling leftward at 2.1m/s. What are their velocities after the collision? If the objects are in contact for 0.010s during the collision, what is the magnitude of the average force that they exert on each other? 2. Relevant equations -v2i + v1i = -v1f + v2f 3. The attempt at a solution Initial Momentum = 0.24kg(3.50m/s) + 0.40kg(2.1m/s) Initial Momentum = 1.68 kg*m/s 1.68kg*m/s = 0.24kg * v1f + 0.40kg*v2f * Now I find a substitution. * -v2i + v1i = -v1f + v2f -v2i + v1i = -2.1m/s + 3.5m/s = 1.40m/s 1.40m/s = -v1f + v2f v2f = v1f + 1.40m/s * Now I substitute it back into the above equation. * 1.68kg*m/s = 0.24kg*v1f + 0.40kg*(v1f + 1.40m/s) 1.68kg*m/s = 0.24kg*v1f + 0.40kg*v1f + 0.56kg*m/s 1.12kg*m/s = 0.64kg*v1f -1.75m/s = v1f (Negative to indicate direction.) * Now I substitute v1f into the original equation. * 1.68kg*m/s = 0.24kg * v1f + 0.40kg*v2f 1.68kg*m/s = 0.24kg * 1.75m/s + 0.40kg*v2f v2f = 3.15m/s I have no idea how to figure out the force exerted on each other. Could someone help here, and also verify that the above answers are correct? Thanks!