AIR RESISTANCE AND TERMINAL VELOCITY
4 marks · NormalA student investigates how the surface area of paper cones affects their terminal velocity. She drops cones of identical mass but different surface areas from the same height and records their terminal velocities.
| Cone Surface Area (cm^2) | Terminal Velocity (m/s) |
|---|---|
| 25 | 3.8 |
| 35 | 3.1 |
| 45 | 2.6 |
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
As the surface area increases, the terminal velocity of the cones decreases. This is because a larger surface area increases air resistance, so the cones reach a lower constant speed before forces balance.
Must show: Describe trend: surface area up, terminal velocity down, Link to increased air resistance, Forces balance at a lower speed
Common mistakes: Describing data without linking to explanation
Show mark scheme and worked solution
Marking points
B1 · 1 mark · Identifies that increasing surface area decreases terminal velocity.
B2 · 1 mark · Describes how greater surface area increases air resistance.
B3 · 1 mark · Explains that a higher air resistance results in forces balancing at a lower speed.
B4 · 1 mark · Uses examples from data or makes a clear scientific link.
Worked solution
The data show that as the surface area of the cone increases from 25 cm² to 45 cm², the terminal velocity decreases from 3.8 m/s to 2.6 m/s. A larger surface area increases air resistance. Therefore, the cone reaches a lower constant speed before the forces are balanced and terminal velocity is reached.