The motion of two identical, moving carts is captured in the graphs below. Cart 1 starts to the left of Cart 2 and is marked with a dashed line. Cart 2 starts to the right of Cart 1 and is marked with a solid line.
The carts are moving in a straight line along the same path. The Velocity vs. Time graphs below show velocity to the right as positive and velocity to the left as negative.
Which graph is consistent with a truly elastic collision?