Consider the collision between two toy carts sliding on a very smooth surface, a
ID: 1626607 • Letter: C
Question
Consider the collision between two toy carts sliding on a very smooth surface, as shown in the figure. The mass of the blue cart is m and the mass of the pink cart is 4m. Initially the blue toy cart moves to the right at speed v and the pink toy cart is at rest. After the collision, the speed of both toy carts is v/3 in opposite directions. Was the collision elastic? Yes No What can we tell about the velocity of the center of mass of the system of the two toy carts just before and after the collision? a) The velocity of the center of mass before the collision is greater than the velocity of the center of mass after the collision. b) The velocity of the center of mass before the collision is less than the velocity of the center of mass after the collision. c) The velocity of the center of mass before the collision is the same as the velocity of the center of mass after the collision. The velocity of the center of mass is always zero.Explanation / Answer
1) to determine the which type of collision (elastic and inelastic)
Just calculate the kinetic energy of the system before and after the collision. If, its conserved then the collision is eleastic otherwise its inelastic
KE before collision = 0.5mv2
KE after collision = 0.5m(v/3)2 + 0.5 x 4m x (v/3)2
= 0.5mv2 / 9 + 2mv2/9
= 2.5mv2/9
Hence KE is not conserved therefore this is an inelastic collision.
Option second is correct.
2) option a is correct because the after collision the velocity is reduce by 1/3 factor.