What is the energy of the air resistance exerted on his parachute?

Question

A parachuter jumped from the top of a building 850 m high with a velocity of 5 m/s. He landed with a velocity pf 2 m/s. What is the energy of the air resistance exerted on his parachute?

Answer 1

Subtract the kinetic energy at the end from the total energy at the beginning and that is the work of the drag force (or the energy dissipated due to the parachute). There is missing information (the mass of the parachuter/parachute). Normally, when no friction is present the initial mechanical energy equals the final mechanical energy and mass cancels - not the case here.