what is the average force of air on the parachute?

Question

A 4000 kg jet touches down at 240 km/h on the deck of an aircraft carrier, and immediately deploys a parachute to slow itself down. If the plane comes to a stop in 155 m, what is the average force of air on the parachute? Assume the parachute provides essentially all the stopping force.

Answer 1

Use X-Xo=Vo t +1/2at^2
and V -Vo=at so t=(V-Vo)/a to get a
then F=ma