Question

which of these situations involves a decrease in chemical potential energy and an increase in kinetic energy?
a) a race car is refueled at a pit stop.
b) a marble accelerates down a ramp.
c) a cell phones battery is being recharged.
d) a battery-powered toy car accelerates from rest.

Explanation:

• Option A: Refueling a race - car at a pit stop involves adding fuel (increasing chemical potential energy), not decreasing it.
• Option B: A marble accelerating down a ramp involves a decrease in gravitational potential energy (not chemical) and an increase in kinetic energy.
• Option C: Recharging a cell - phone battery involves an increase in chemical potential energy (electrochemical reactions store energy in the battery).
• Option D: In a battery - powered toy car accelerating from rest, the chemical reactions in the battery (decreasing chemical potential energy) provide energy. This energy is converted into the kinetic energy of the moving car (increase in kinetic energy).

Answer:

D. A battery - powered toy car accelerates from rest.