A body, of mass m, falls from rest at a height y,. If the drag (resisting) force of air is assumed to be proportional to the instantaneous velocity v of the body. Use k as the proportionality constant and take (y = 0) at ground level. (1) Find the height of the body y as a function of its velocity v. (2) Find the height of the body y as a function of time t. (3) Assuming that g = 9.81 m/s², m = 1 kg, y, = 2000 m and k = 0.01, calculate the height of the body 20 seconds after it starts falling.

A body, of mass m, falls from rest at a height y,. If the drag (resisting) force of air is assumed to be proportional to the instantaneous velocity v of the body. Use k as the proportionality constant and take (y = 0) at ground level. (1) Find the height of the body y as a function of its velocity v. (2) Find the height of the body y as a function of time t. (3) Assuming that g = 9.81 m/s², m = 1 kg, y, = 2000 m and k = 0.01, calculate the height of the body 20 seconds after it starts falling.