3. A low friction cart (similar to what you use in the lab) collides with a second low friction cart.

Question

Cart A has a mass of 0.500 kg and cart B has a mass of 0.750 kg. Glider A was moving at 40.0
cm/s before the collision. Glider B was at rest.
(a) The carts have velcro on them so that they stick together during the collision. What quantities
are conserved in this collision?
(b) How fast are they moving after the collision?
1
PHYS 1101 Assignment #9 Due: Thurs., Nov. 19
(c) Compare the kinetic energy of the two-cart system before the collision with the kinetic energy
after the collision. Was there any “deformation” of the carts? If so, what was the nature of
this deformation?
(d) Now suppose the carts are (like the ones in the lab) equipped with magnets so that they
repel each other. Now the carts don’t even touch each other during the “collision” and so
no deformation of either cart can take place. Suppose the collision is otherwise the same as
before (same initial velocities). Find the velocities of the carts after the collision now.

Answer 1

3a. Momentum conserved.

b. Ma*Va + Mb*Vb = Ma*V + Mb*V.
0.50*0.40 + 0.750*0 = 0.50V + 0.75*V.
V = ?

c. Before: KE = 0.5Ma*Va^2.
After: KE = 0.5(Ma+Mb)*V^2.
KE will be less after the collision.