A 50.0 kg child is riding in a 120.0 kg bumper car at an amusement park. The child drives the
bumper car at 4.5 m/s head-on into the wall of the ride and rebounds at the speed. What is the
magnitude of the change in momentum of the child in the bumper car?

the first american roller coaster was the mauch chunk switchback railway, built in the mountains of pennsylvania in the mid-1800s. the track, originally built to send coal to a railway, was reconfigured as a "scenic tour."

i think the answer is a, hope this : )

that would be because of both gravity and friction. so     c