3. A designer is designing a new parachute, starting from scratch, and needs an initial estimate of the required drag coefficient. The designer coniosiders a case in which a skydiver jumps out of a plane at an altitude of 30,000 ft (~ 10,000 m), and assume that the skydiver can be considered a cylinder of diameter 0.4 m and length 1.8 m, with a mass of 70 kg. If the Reynolds number is always high, it can be safely assumed that the drag coefficient is independent of Reynolds number. (a) Write down the equation of motion governing velocity as a function of time. (b) Assume free fall for 20 seconds, after which the parachute opens (b) If the velocity with which the skydiver approaches the ground cannot be more than 1 m/s, what is the drag coefficient of the parachute? (20 points)