5-22 Equation Reference
Variable
Description
A
Pro
ected area relative to flow
ar
Centri
etal acceleration at r
at
Tan
en
ial acceleration at r
Cd
Dra
coefficien
E
Ener
F
Force at r or x, or Spring force (Hooke's Law), or attractive
force
Law of Gravitation
or Dra
force
Dra
force
I
Moment of inertia
k
S
rin
constan
Ki,Kf
Initial and final kinetic ener
ies
m, m1, m2
Mass
N
Rotational s
eed
Ni, Nf
Initial and final rotational s
eeds
P
Instantaneous
owe
Pavg
Avera
e
owe
r
Radius from rotation axis, or
Se
aration distance
Law of Gravitation
t
Time
v
Velocit
vf, v1f, v2f
Final velocit
vi, v1i
Initial velocit
W
Work
x
Dis
lacemen
Reference: 3.
Linear Mechanics (4, 1)
Equations:
Fma⋅=Ki
1
2
---
mvi
2
⋅⋅=
Kf
1
2
---
mvf
2
⋅⋅=
WKfKi–=
vf vi a+t⋅=
PFv⋅=
Pavg
W
t
-----
=
WFx⋅=
Example:
Given: t=10_s, m=50_lb, a=12.5_ft/s^2, vi=0_ft/s.
Solution: vf=125_ft/s, x=625_ft, F=19.4256_lbf, Ki=0_ft
∗
lbf, Kf=12140.9961_ft
∗
lbf, W=12140.9961_ft
∗
lbf,
Pavg=2.2075_hp.