### Parachuting

A person who weighs 77 kg. is parachuting, with a downward acceleration
of 2.5 $m/s^{2}$ shortly after opening the parachute. The mass of
the parachute is 5.2 kg.

a) Find the upward force exerted on the parachute by the air.

b) Calculate the downward force exerted by the person on the parachute.