Crib sheet

Nomenclature

a = acceleration of object falling in a vacuum, (m/s2)
af = acceleration of object falling in a fluid, (m/s2)
A = characteristic area for the object, (m2)
d = diameter of sphere, (m)
Cd = dimensionless drag coefficient
Fd = drag force, (N)
Fp = drag force on deployed parachute, (N)
Fs = drag force on skydiver without a parachute, (N)
g = gravitational acceleration, (m/s2)
k = drag coefficient, (Ns2/m2)
m = mass of object, (kg)
R = Reynolds number,
t = time, (s)
v = velocity of object falling in a vacuum, (m/s)
vf = velocity of object falling in a fluid, (m/s)
vr = relative velocity between fluid and object, (m/s)
Vt = terminal velocity, (m/s)

Subscripts

f = refers to fluid
p = refers to parachute

Greek Symbols

pf = fluid density, (kg/m3)
uf = fluid viscosity, (Ns/m2)

Equations

1.1
1.2
1.3 v(t=0)=0
1.4 v=gt
2.1
2.2
2.3
2.4 v(y=0)=0
2.5
3.1
3.2
3.3 vf=(t=0)=0
3.4
4.1
6.1
6.2
7.1
7.2
7.3
7.4 mg-kv2f=0
9.1 v(t=t0)=v0=0.977
9.2 v(t)=v0+g(t-t0)
9.3
9.4
9.5
9.6
9.7
9.8
9.9
9.10
9.11
9.12

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