A block of mass m 5 kg slides with an initial speed vi = 5 m/s to the right towa
ID: 1789508 • Letter: A
Question
A block of mass m 5 kg slides with an initial speed vi = 5 m/s to the right toward a ramp of mass M = 20 kg. The ramp itself can also slide without friction on the surface and has a frictionless face that the block can slide upon. The block slides up the ramp so that its center of mass rises a maximum height h, then back down until it is separated from the ramp. Let velocities to the left be indicated by a negative (a) Determine the speed vh of the block-ramp system at the instant the block reaches its maximum height on the ramp m/s (b) Determine the height h to which the block's center of mass rises meters (c) Determine the final velocities vf and vr of the block and ramp, respectively Final velocity of the block Final velocity of the ramp = xm/s X m/sExplanation / Answer
Applying momentum conservation again,
5 x 5 + 0 = - 5 vf + 20 vr
4 vr - vf = 5
vf = 4 vr - 5
Applying energy conservation,
(5 x 5^2 / 2) = 20 vr^2 /2 + 5 vf^2 / 2
125 = 20 vr^2 + 5 (16 vr^2 - 40 vr + 25)
125 = 20 vr^2 + 80 vr^2 - 200 vr + 125
100 vr^2 - 200 vr = 0
vr = 2 m/s
vf = 3 m/s
final velocity of block = - 3 m/s
final velocity of ramp = 2 m/s