AIR RESISTANCE AND TERMINAL VELOCITY
4 marks · NormalA toy parachute is dropped from a tall building.
Draw and label all the forces acting on the parachute immediately after it is released.
Describe how the size of each force changes as the parachute falls and eventually reaches terminal velocity.
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.
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(a) Downward force labelled 'weight' (or gravity) and upward force labelled 'air resistance' (or drag) · must show weight arrow down, air resistance arrow up, both labelled
(b) Weight stays the same; air resistance increases as parachute speeds up, until it balances weight at terminal velocity. · must show weight constant, air resistance increases, forces equal at terminal velocity, resultant force zero (object falls at constant speed)
Show mark scheme and worked solution
Marking points
M1 (a) · 1 mark · Correctly shows and labels downward force (weight)
M2 (a) · 1 mark · Correctly shows and labels upward force (air resistance or drag)
B1 (b) · 1 mark · States that weight is constant and air resistance increases as parachute speeds up
B2 (b) · 1 mark · States forces become equal so there is no resultant force and terminal velocity is reached
Worked solution
a) There are two main forces: weight acts downward, and air resistance acts upward. Both should be shown as arrows beginning at the parachute, with correct direction and labels.
b) The weight of the parachute remains the same during the fall. As the parachute moves faster, the air resistance increases. Eventually, the air resistance becomes equal to weight, so the resultant force is zero, and the parachute falls at constant (terminal) velocity.