Trevor places a mass on a spring. when he releases it, the mass and spring move in simple harmonic motion.

how could trevor increase the amplitude of the motion?

he could use a longer spring.
he could use a smaller mass.
he could use a stiffer spring.
he could pull the mass down farther.

Arailroad car collides with and sticks to an identical railroad car that is initially at rest. after the collision, the total kinetic energy of the two cars is a) the same as before. b) half as much as before. c) one third as much as before. d) one fourth as much as before. e) twice as much as before.