Logistics
May18-05, 09:06 AM
This is my 3rd practice question that I don't know how to do :( Hoping peole can help me out, if someone could even work it out, would be greatly appriciated.
A skydiver, weighing 70kg, jumps from an aeroplane at an
altitude of 700 metres and falls for T1 seconds before pulling
the rip cord of his parachute. A landing is said to gentle if
the velocity on impact is no more than the impact velocity of
an object dropped from a height of 6 metres. The distance
that the skydiver falls during t seconds can be found from New-
ton’s Second Law, F = ma. During the free fall portion of
the the jump, we will assume that there is essentially no air
resistance, so F = −mg where g = 9.8ms^−2 and m = 70kg.
After the parachute opens, a significant drag term due to the
air resistance of the parachute affects the force F, causing the
force to become F = −mg − kv where v is the velocity and
k = 110kg/sec is a drag coefficient.
(a) Find the range of times T1 at which the rip cord can be
pulled for a gentle landing.
(b) Find the height after T1 seconds of free-fall.
A skydiver, weighing 70kg, jumps from an aeroplane at an
altitude of 700 metres and falls for T1 seconds before pulling
the rip cord of his parachute. A landing is said to gentle if
the velocity on impact is no more than the impact velocity of
an object dropped from a height of 6 metres. The distance
that the skydiver falls during t seconds can be found from New-
ton’s Second Law, F = ma. During the free fall portion of
the the jump, we will assume that there is essentially no air
resistance, so F = −mg where g = 9.8ms^−2 and m = 70kg.
After the parachute opens, a significant drag term due to the
air resistance of the parachute affects the force F, causing the
force to become F = −mg − kv where v is the velocity and
k = 110kg/sec is a drag coefficient.
(a) Find the range of times T1 at which the rip cord can be
pulled for a gentle landing.
(b) Find the height after T1 seconds of free-fall.