Free fall

Question 1

Identify the significant forces acting on an object falling freely under gravity

Answer 1

• See notes page

Question 2

Use force concepts to describe and explain the free-fall motion of an object in both the presence and absence of resistive forces

Answer 2

1. At time = 0s, the object accelerates as there is a resultant force downwards with maximum acceleration
2. At time = 2s, air resistance increases, there is a smaller acceleration downwards
3. At time = 7s, reaches terminal velocity, constant velocity, force upwards = force downwards
4. At time = 9s, opens parachute, air resistance is larger than weight, accelerates upwards, falls slower
5. At time = 12s, new slower terminal velocity, W = AR

Question 3

Describe what is meant by terminal velocity and why it arises.

Answer 3

• Terminal velocity is when air resistance = acceleration (weight or mg), where the resultant force is 0 and the object falls at a constant velocity