Packages on a Conveyor Belt:
Two packages "B" and "C" are at rest on a horizontal roller conveyor in the mail room as shown. The rollers
are frictionless so the packages can move freely without resistance. A third package, "A", moving to the right
at vAi collides with "B". The velocities of the packages "A" and "B" after the impact are vAf and vBf .
Package "B" moving at vBf collides with “C” initially at rest. The mass of each package is given, and the
coefficient of restitution is 0.80 between all of the packages.
a. Draw appropriate sketches below to analyze the collision between A and B.
b. Write down momentum conservation equation and the relative velocity equation for the impact
between the packages "A" and "B".
Use symbols m A, mB, vAi , vBi , vAf and vBf only.
c. Determine the magnitude and direction of the velocities of "A" ( vAi and vAf ) before and after the
impact if vBf = 1.2 i m/s .
d. What is the average impulsive force on "A" if the impact lasts just 0.30 seconds?
e. Write down momentum conservation equation and the relative velocity equation for the impact
between "B" and "C".
Find the magnitude and direction of velocities of "B" and "C" immediately after "B" strikes "C".
VAi
A
y
x
0.6 m
B
C
Masses: mA = 3mB ; mB = mC = 6 kg