Effect of parachute on free fall?

[pihotar]

I was told i have till wednesday to do a project on physics I've never done before in class, this being a regular high school physics class. So i decided to figure out how a parachute affects free fall and the calculations and stuff to show this.

So far I've found an Air Resistance formula that goes like this:
F-air=0.5pv(squared)AC(sub-d)V
I don't know how to type the squared sign so i wrote it in, and the C(sub-d) refers to the d being sort of like an exponent but below instead of above the letter.

Cd I've learned is called the drag coefficient, but to calculate that I've found several formulas that i cannot understand amongst the internet and i need help understanding the formula.

Also i was thinking of using the formula to determine the air resistance of a free falling man and the velocity and then comparing it to the same calculation with a parachute and seeing the difference in speed to where youd survive the fall. Do you think it would work?

Also also would i be able to find out the decelleration effect of a parachute on a drag racing car in any way?

Thank you for your time, Pihotar

 

[jhae2.718]

I was told i have till wednesday to do a project on physics I've never done before in class, this being a regular high school physics class. So i decided to figure out how a parachute affects free fall and the calculations and stuff to show this.

It's a good idea for a project, but air resistance adds quite a bit of complexity so you may be cutting it close on time.

So far I've found an Air Resistance formula that goes like this:
F-air=0.5pv(squared)AC(sub-d)V
I don't know how to type the squared sign so i wrote it in, and the C(sub-d) refers to the d being sort of like an exponent but below instead of above the letter.

I'm not sure why you have the V in there, but yes, drag is given by:
$$F_{drag} = C_D \frac{1}{2}\rho V^2 A$$

Like you've said, $C_D$ is the coefficient of drag.
$\rho$ is the density of air
V is the velocity
A is the cross sectional area facing the air flow.

Cd I've learned is called the drag coefficient, but to calculate that I've found several formulas that i cannot understand amongst the internet and i need help understanding the formula.

The drag coefficient is usually determined experimentally. You can probably find values for the drag coefficient for a parachute online. You could also do your own experiment with a small parachute to find the drag force, and then use the drag equation to find $C_D$.

Also i was thinking of using the formula to determine the air resistance of a free falling man and the velocity and then comparing it to the same calculation with a parachute and seeing the difference in speed to where youd survive the fall. Do you think it would work?

You could do this. The difficulty you'll have here is that you'll need to solve a differential equation to find the speed. You'll probably have to solve it numerically with a spreadsheet or a programming language.

Also also would i be able to find out the decelleration effect of a parachute on a drag racing car in any way?

Yes. If you can find the drag coefficient for the parachute and you know the speed of the racer, you can describe the dynamics of the car.

 

[pihotar]

So say i have a velocity of 53 m/s, p = 1.22, Cd= 1.5, nd the area of my parachute is, i don't know 5 meters, th force of air resistance would be 12851.1? I don't know the unit of measure for it and i just want to make sure that my calculatio is right because thatrs a pretty huge number.

 

[jhae2.718]

That calculation would be correct, yes. If you use MKS units, force is in Newtons, and you would need the air density in kg/m^3. The unit for area is m^2, by the way.

Since the drag force is a function of velocity squared, at high speeds the drag force becomes very large.