A skydiver jumps from an aircraft and falls vertically downwards. Describe how the velocity of the skydiver changes from the moment they leave the aircraft until they reach terminal velocity. Explain the reasons for each change in velocity.

Model answer (5 marks)

Examiner tips

• Use the word ‘accelerates’ for the initial phase and ‘decreases’ for the rate of acceleration.
• Show the relationship F_net = mg – F_drag and explain how F_drag increases with velocity.
• Mention that terminal velocity occurs when F_drag = mg and F_net = 0.
• Use correct terms: weight, air resistance, terminal velocity, resultant force.

Common mistakes

• Confusing acceleration with velocity – students write ‘velocity increases’ instead of ‘accelerates’.
• Forgetting to state that the resultant force becomes zero at terminal velocity.
• Using incorrect terminology such as ‘speed’ instead of ‘velocity’ or ‘drag’ instead of ‘air resistance’.