Final answer:
The calculated change in momentum of the cart does not always equal the measured impulse applied to it by the wall during a nearly elastic collision. This is because the impulse is used to both change the cart's velocity and its direction.
Step-by-step explanation:
In a nearly elastic collision between a cart and a wall, the calculated change in momentum of the cart does not always equal the measured impulse applied to it by the wall.
This is because during an elastic collision, the kinetic energy is conserved, so some of the impulse is used to change the cart's velocity, while the rest is used to change its direction.
Therefore, while the calculated change in momentum provides information about the magnitude of the impulse, it does not account for the change in direction.