A container with mass M kg is dropped by a helicopter from height H km at time t = 0, with zero velocity. From the outset, its fall is controlled by gravity and the force of air resistance, f (v) = − kv, where v is the current velocity of the container. In 7 seconds after the drop, a parachute opens, resulting in an increase of air resistance up to F(v) = -Kv. Determine the time T at which the container touches the ground, and its velocity at this moment, if M = 200 kg, H = 2000 m, 7 = 20 s, k = 10 kg/s, and K = 400 kg/s.

A container with mass M kg is dropped by a helicopter from height H km at time t = 0, with zero velocity. From the outset, its fall is controlled by gravity and the force of air resistance, f (v) = − kv, where v is the current velocity of the container. In 7 seconds after the drop, a parachute opens, resulting in an increase of air resistance up to F(v) = -Kv. Determine the time T at which the container touches the ground, and its velocity at this moment, if M = 200 kg, H = 2000 m, 7 = 20 s, k = 10 kg/s, and K = 400 kg/s.