Physics Cheat Sheet
1 Units
SI: m, kg, s
area: m2, volume: m3
velocity: m/s, acceleration: m/s2
Common Conversions
1. 3600 s= 1 hour
2. 5280 ft = 1 mile
3. 1.094 yards = 1 meter
4. 1.609 km = 1 mile
5. 2.54 cm = 1in
6. 1 m/s = 2.237 mi/hr
7. 745.7W atts = 1 hp (Hor seP ower)
8. 1 mL = 1 cm3
Common Physical Constants
1. c= 2.998 ×108m/s (Speed of Light)
2. g= 9.81 m/s2= 32.2ft/s2
3. gmoon = 1.62 m/s2≈1
6gearth
4. G= 6.674 ×10−11N m2/kg2
5. Re= 6380 km (Earth Radius)
6. Rearth−moon = 60Re(Earth-Moon Distance)
7. Rearth−sun = 150 million km (Earth-Sun)
8. ρair = 1.2041kg/m3= 0.0012041 g/cm3
9. ρwater = 1 g/cm3
2 Density
ρ=m
V
Objects less Dense than Water will rise in Water.
Objects less Dense than Air will rise in Air.
3 Motion: 1D
Speed must be positive, velocity can be positive or
negative
vav =∆x
∆t,v= slope of xvs. tcurve
aav =∆v
∆t,a= slope of vvs. tcurve
Constant Acceleration Processes
a=constant
v=v0+at
x=x0+v0t+1
2at2
v2=v2
0+ 2a∆x(Handy Eq.)
Motion with Gravity: a=−g
4 Motion: 2D
Constant Acceleration Processes
ax= 0 ay=−g
vx=vx0vy=vy0−gt
x=x0+vx0t y =y0+vy0t−1
2gt2
Handy Eq.
v2
x=v2
x0v2
y=v2
y0−2g∆y
v2=v2
0−2g∆y
Vector Velocity
vx=v0cos(θ)vy=v0sin(θ)
5 More Motion Formulas
R0=v2
0
gsin(2θ) [Note: sin(2θ) = 2sin(θ)cos(θ)]
ymax =v2
0
2gsin2(θ)
Tflig ht =2v0
gsin(θ)
y(x) = tan(θ0)x1−x
R0
R=R0
2h1±q1−h
ymax i
θmax range =π
4+gh
2v2
0
6 Newton’s Laws of Motion
1. v=constant if Fnet = 0
2. Fnet =ma
3. Action = Reaction, F12 =−F21
4. F=−Gm1m2
R2
7 Forces
Fgrav =−GM m
R2. Near Earth Fgrav =mg.
Ffr ic =µN
Fspring =−kx
Fbuoy =ρV g
Fdrag =1
2CDρAv2
vT=q2mg
CDρA
vT(mi
hr ) = 0.45566√m(ingrams)
D(in mm)(spherical objects)
8 Energy
units: Joules (N·m)
Energy is neither created nor destroyed
1
2mv2
|{z }
KE
+mgh
|{z}
P E
=1
2mv2
0
|{z }
KE0
+mgh0
|{z }
P E0
Types of Energy
1. Mechanical Energy
2. Thermal Energy
3. Electrical Energy
4. Magnetic Energy
5. Light Energy (Electromagnetic)
6. Sound Energy (Acoustic)
7. Chemical Energy
8. Nuclear Energy
Power
units: Watts (J/s)
Power = Rate of Energy Flow
Pav =∆E
∆t
9 Circular Motion
Centripetal means towards the center of the circle
acentrip =v2
r,Fcentrip =mv2
r
T= 2πr/v (Tis period of motion)
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