Question

A roller coaster car with a mass of 920.5 kg starts from rest at the top of a 47.1 m hill labeled h1. The car travels to the bottom of the hill and continues up the next hill that is 12.5 m high and labeled h2.

a.) Ignoring friction, what is the speed of the roller coaster car at the bottom of the hill?

b.) Ignoring friction, what is the speed of the roller coaster car at the top of the second hill?

c.) Ignoring friction, what is the work done on the roller coaster car as it moves from the top of h1 to the bottom of the hill?

d.) Ignoring friction, what is the work done on the roller coaster car as it moves from the bottom of the hill to the top of the second hill?

Answer 1

1) at the top total energy = potential energy = mgh1

and at the bottom total energy is kinetic energy= 0.5 mv^2

so, eqivating both

we get

v= 30.38 m/s

2) at the top of second hill total energy

so frok conservation of energy

so solving for v2

we get

v2 = 26.04 m/s

3) from work energy theoram

so we get

W= 424.78 kJ

4) so same here

W= -112.7 kJ