Finding terminal velocity of a skydiver with parachute using drag force

[physics_newb]

Homework Statement

The drag coefficient works like the coefficient of friction when an object is moving through the air, but it increases its effects as the object moves faster. A skydiver plus the parachute has a combined mass of 94.0kg. if the formula for the drag coefficient of the parachute is F_fric=C_D v^2, find the terminal velocity of the 54.0kg/m

Homework Equations

m=94.0kg a=9.8m/s^2
Cd=54.0kg

The Attempt at a Solution

I do not understand the question and am not even sure what terminal velocity is in the first place

 

[ideasrule]

As an object falls under gravity, air resistance gets stronger and stronger. Eventually, at a certain speed, air resistance will equal the force of gravity and the object stops accelerating. So what's the first step?

 

[physics_newb]

Oh ok how do you find out when that point is?

 

[ideasrule]

At that point, the force of gravity is equal to the force of air resistance. Write that out as a formula and you're basically done.

 

[physics_newb]

Fg=Fa?

 

[ideasrule]

Yes.

 

[physics_newb]

so there isn't any answer?

 

[ideasrule]

Fg=?
Fa=?

Write them out using the information you know and the information you want to find (namely, Cd, v, m, and g).

 

[physics_newb]

ok ill try and post back

 

[ideasrule]

You already got one:

F_fric=C_D v^2

What's Fg?

 

[physics_newb]

Fg is 9.8m/s/s

 

[ideasrule]

That's g, the acceleration due to gravity. F=ma, so Fg=?

 

[physics_newb]

921.2m/s/s?

 

[physics_newb]

wow i need serious help with this

 

[ideasrule]

Fg=mg. Remember this.

 

[physics_newb]

ok i think i might have gotten it...is this all i have to do:
m=94.0kg
a=9.8m/s^2
CD=54kg/m
v=?
F_fric=?
Step 1
F_fric=ma
F_fric=94.0*9.8
F_fric=921.2m/s
Step 2:
921.2=54*v^2
921.2/54=v^2
17.1=v^2
√17.1=v
4.1=v
v=4.1m/s

 

[physics_newb]

is it right?