In this question i and j are the unit vectors due east and due north respectively, and k is the unit vector acting vertically upwards. A BASE jumper descending with a parachute is modeled as a particle of mass 50 kg subject to forces describing the wind, W, and air resistance, F, where:

W = (20i + 16j) N

F = (−4i − 3j + 450k) N

a. With reference to the model, suggest a reason why the k component of F is greater than the other components.

b. Taking g = 9.8 m s⁻², find the resultant force acting on the BASE jumper.

c. Given that the BASE jumper starts from rest and travels a distance of 180 m before landing, find the total time of the descent.