A parachutist jumps from a stationary helicopter and falls vertically downwards. After a short time, the parachutist opens their parachute and eventually reaches terminal velocity. Explain the energy transfers that occur from the moment the parachutist leaves the helicopter until they reach terminal velocity.

1. At the instant the parachutist leaves the helicopter, they possess gravitational potential energy (GPE) relative to the ground.
2. As they fall, GPE decreases and is converted into kinetic energy (KE), increasing their speed.
3. Simultaneously, work is done against air resistance (drag), which removes energy from the system and transfers it to the surroundings as thermal energy (heat).
4. When the parachute opens, the drag force rises sharply, so more work is done against air resistance per unit distance, further converting GPE into heat.
5. At terminal velocity the rate of GPE loss equals the rate of energy dissipated as heat; the parachutist’s KE remains constant, so no further energy is transferred to KE.