Question

Kinetic energy changes into potential energy.

Kinetic energy changes into frictional energy.

Potential energy changes into kinetic energy.

Why is a roller coaster fastest at the bottom of a hill?

(1 point)

Thermal energy changes into potential energy.
O

O

Answer 1

A roller coaster is fastest at the bottom of a hill because gravitational potential energy (PE) has been converted into kinetic energy (KE) as it descends. At the lowest point PE is at its minimum, so KE (and thus speed) is at its maximum. (Ignoring losses, mgh = 1/2 mv^2.)

Which statements are correct:
- Kinetic energy changes into potential energy. — True (when it climbs).
- Kinetic energy changes into frictional energy. — True (friction/air resistance converts KE to thermal).
- Potential energy changes into kinetic energy. — True (when it descends).
- Thermal energy changes into potential energy. — False (thermal energy does not generally convert into gravitational potential in this context).