Question

I AM GIVING 95POINTS HELP PLEASE!!

Look up Luke Aikins No Parachute 25,000 Feet Airplane Jump Complete Video on YT and watch the 3 min video to answer these please.

Please answer the following questions related to this feat. Answer all your questions using your understanding of physics. Show equations and all work.

How high was his jump in meters?

Assuming Luke has a mass of 90Kg how much potential energy does he have just as he leaves the plane? Explain how you know.

With what force does gravity pull him toward the earth? Explain how you know.

What is his acceleration just as he leaves the plane? Explain how you know.

If there was no wind resistance how fast would Luke be going just before he hits the net? Explain how you know.

Wind resistance slows Luke to 150MPH. How fast is this in meters /sec?

Is Luke still accelerating when he is falling at 150MPH? Explain.

What is the force of wind resistance on Luke once he is falling at 150MHP?

If there were no wind resistance what would Luke’s Kinetic Energy be just before he hits the net?

Luke was unhurt after landing in a net. How is this possible? Explain how the net prevented any injury to Luke. Use terms like impulse, force, momentum and time.

Answer 1

This is a fun question - your science teacher is creative!

First is easy, 25000 feet converts to 7620 meters

Potential energy is a product of mass, gravity and height. In this case, mass is 90Kg and height is 7620m. gravity on earth is 9.8m/s2.

Potential energy = 90(9.8)(7620) = 6720840J

By Newton 2nd law, force is equal to mass times acceleration.

Gravity force = mass*gravity

= 90(9.8) = 882N

Acceleration when he leaves the plane is gravity, 9.8m/s2

With no wind resistance, the acceleration is constant at 9.8.

Using kinematic equation, v2 = u2 + 2as where u is initial velocity, v is final velocity, a is acceleration and s is distance traveled.

In this case, u=0, a=9.8, s=7620

v^2 = 2(9.8)(762) = 149352

final velocity = sqrt (149352) = 386.5m/s

150MPH converts to 67m/s.

If he is falling at a constant speed of 150MPH, then he is not accelerating.

As he is not accelerating, the net force = gravity force - wind resistance = 0

wind resistance = gravity force

= 90(9.8) = 882N

If there is no wind resistance, by conservation of energy,

final Kinetic Energy = initial Potential energy

= mass * gravity * height

= 90*9.81*7620

= 6720840J

He is unhurt because the safety net provides a soft landing. It decelerates his momentum gradually over time to avoid injury.

Answer 2

25,000 Feet = 7620m

PE = mgh where m is mass, g is gravity accel: 9.8 n h is height

= 90 x 9.8 x 7620

= 6720840J

= 6.72MJ

F = ma where m is mass, a is accel = gravity = 9.8

= 90 x 9.8

= 882N

Accel = gravity = 9.8m/s^2

KE = 1/2mv^2 where m is mass n v is vel

if no wind resistance, PE leaving airplane = KE at net

6720840 = 1/2 x 90 x v^2

v^2 = 149352

v = 386.5m/s

150MPH=67m/s

@150MPH, his speed is not changing so accel=0

accel=0, force=0 by newton's second law

force=0 when wind resistance = gravity = 9.8m/s^2

by conservation of energy, Luke's KE = PE = mgh = 6720840J

he was unhurt cuz' his momentum was absorbed by the net