## I need to find out how long of a runway i would need to safely accelerate a human being to 22,500 mph

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# I need to find out how long of a runway i would need to safely accelerate a human being to 22,500 mph

I need to find out how long of a runway i would need to safely accelerate a human being to 22,500 mph!!

factor:

I’m not sure what the maximum G force a 60 year old person could safely experience. so let’s go with a 5 G force maximum.

PLEASE SOMEONE HELP

Hi Kinseybeck,

The G Force that a 60 year old person could take depends on how sportive the person is. Let’s assume that it is possible! (Which may be the real case)

1 G force is assumed as 9.8 m/s2 which is 127008 km/h2.

And you’d like to reach to speed 22500 mph which is 36204.103671706 km/h.

Basic equation V=a*t then 36204 = 5*127008*t,

We find time as t= 0.05701058201 hours. This is the time needed to reach that speed with your acceleration.

Then runway (X), X=V*t,

X= 0.05701058201*36204= 2064.01111109 km.

But this calculation does not take into account the friction. You will definitely need to calculate friction as you are doing your experiment on the world not in space.

To calculate the friction, first you need to calculate the resulting force of the person. (We assume that only the person accelerates by itself).

Fperson=m*g (mass*acceleration)

To find its mass, you can use mass=weight/Gforce

Then you can calculate Fperson.

Ffriction = u*Fperson. u is the friction coefficient of the material of your runway. Here you have the Friction Force!

Remember that Fnet=Fperson-Ffriction;

Then a=Fnet/m. So here you have the new acceleration with the effect of friction. Now you can go up and re-do your calculations.

Hope that helps you out!

Aerospaceengineering.Aero

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