A parachutist of total mass 90kg (including the parachute) is falling at a terminal velocity of 6m/s. Take the force due to gravity on a mass of 1kg to be 10N. What is the magnitude of the air resistance force acting on her?

Answer:

17) D

Since the parachutist has reach terminal velocity, the resultant force (i.e. sum of forces acting on the parachutist) will be zero.

The forces acting on the parachutist would be the weight and air resistance.

Weight = 90 x 10 = 900 N

Since resultant force is zero, weight = air resistance

So air resistance = 900 N