Figure 2: Velocity-time graph for a skydiver — note the changing gradient and the effect of opening the parachute
The gradient (slope) of a velocity-time graph tells you the acceleration at any point.
- Steep positive gradient at the start — large resultant force, large acceleration (about 10 m/s²)
- Decreasing gradient — drag is increasing, resultant force decreasing, acceleration decreasing
- Zero gradient (horizontal line) — terminal velocity reached, resultant force = 0, acceleration = 0
- Negative gradient after parachute opens — drag suddenly much greater than weight, so deceleration occurs
- New horizontal line at lower speed — new (lower) terminal velocity with parachute open
The area under a velocity-time graph gives the distance travelled. This is useful for calculating how far a skydiver has fallen at any point.
Quick Check: A skydiver is falling at a constant velocity of 55 m/s. What is the resultant force acting on them?
Zero. At terminal velocity, weight equals drag, so the resultant force is zero. This means acceleration is also zero (F = ma: if F = 0, a = 0).
This deep dive covers Velocity-Time Graphs for Falling Objects within Terminal Velocity for GCSE Physics. Revise Terminal Velocity in Extra Topics for GCSE Physics with 13 exam-style questions and 11 flashcards. Use this page as part of a wider topic revision path rather than treating it as an isolated fact. It is section 3 of 13 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Terminal Velocity
An object reaches terminal velocity when falling through air. Which statement correctly describes the forces at terminal velocity?
Explain how a skydiver reaches terminal velocity after jumping from a plane. Include changes to forces and acceleration in your answer.