In: Mechanical Engineering
A parachutist whose mass is 65 kg drops from a helicopter
hovering 2000 m above the ground and falls toward the ground under
the influence of gravity. Assume that the force due to air
resistance is proportional to the velocity of the parachutist,
with the proportionality constant b1 = 20 N-sec/m when
the chute is closed and b2 = 90 N-sec/m when the chute
is open. If the chute does not open until the velocity of the
parachutist reaches 25 m/sec, after how many seconds will the
parachutist reach the ground? Assume that the acceleration due to
gravity is 9.81 m divided by sec squared.
The parachutist will reach the ground after
_______ seconds.
(Round to two decimal places as needed.)