A roller coaster moves downhill at 30 in/s and then climbs up a hill at 4 m/s. The momentum of the roller
coaster
a. is zero throughout the ride.
b. is greater down the hill than up the hill.
C. is greater up the hill than down the hill.

Which explanation describes the forces involved for a person to walk down the sidewalk? a. the person's feet push backward on the sidewalk; the sidewalk pushes backward on the person. b. the person's feet push forward on the sidewalk; the sidewalk does not push on the person. c. the person's feet push backward on the sidewalk; the sidewalk pushes forward on the person. d. the person's feet push forward on the sidewalk; the sidewalk pushes forward on the person.

Determine the fraction of the magnitude of kinetic energy lost by a neutron (m1 = 1.01 u) when it collides head-on and elastically with a target particle at rest which is 21h (heavy hydrogen, m = 2.01 u).

An isotope undergoes radioactive decay by emitting radiation that has a –1 charge. what other characteristic does the radiation have?