In a physics lab, a small cude slides down a frictionless incline, and elastically strikes a cube at the bottom of the inclince that is only one-half its mass. If the incline is 30 cm high and the table is 90 cm off the floor, where does each cube land?

Question

I got the V0 to be 2.43 from mhg = 1/2mv^2 but after setting up M1V1=M1V1' + M2V2' i don't know what to do

Answer 1

The speed of the sliding cube at impact is V = sqrt(2gH) = 2.42 m/s

Next you have to figure out the velocities of the sliding cube (mass M) and the impacted cube (Mass M/2), after impact. You need to write equations of both momentum and kinetic energy conservation. You will find, if you do it right, that the smaller cube travels at 4V/3 and the larger cube at V/3.

Finally, use those horizontal velocities and the height of the table to predict where they land.