Different exam boards may want a different format of answer, so before beginning this question, it would be worth thinking how other six mark questions are marked in other papers.
Edexcel want the student to break down their answer as such:
- Establish which forces are acting
- How the magnitude of the forces changes during the fall, affected by what
- The stages the skydiver will experience as they fall through the air
Here, the question wants simple answers to begin with, then they get more involved for higher marks.
- Forces acting are weight downward, and air resistance upwards (opposing the weight)
- As the skydiver falls, though their weight stays the same, their air resistance increases with speed. This can be shown by a simple equation: resultant force = W - R. This means that while R (air resistance) is less than W, the resultant force will be greater than 0, and the skydiver will continue to accelerate.
- at the start, the skydiver's weight exceeds air resistance, so they have a large acceleration. as their speed increases, so does air resistance, so the resultant force (and acceleration) decreases. When they reach terminal velocity, resultant force is 0 (W = R), and so is acceleration, so they have reached a constant speed.
The concepts in this question can be difficult for the first time, but a with tailored explanation from me, you'll soon understand!