PHYSICS FORMULAS
2426
Electron
=
1.602 19 × 10
19
C
=
9.11 × 10
31
kg
Proton
=
1.602 19 × 10
19
C
=
1.67 × 10
27
kg
Neutron
=
0 C
=
1.67 × 10
27
kg
6.022 × 10
23
atoms in one atomic mass unit
e
is the elementary charge: 1.602 19 × 10
19
C
Potential Energy, velocity of electron:
PE =
eV
= ½
mv
2
1V = 1J/C
1N/C = 1V/m
1J = 1 N·m = 1 C·V
1
amp
= 6.21 × 10
18
electrons/second
= 1
Coulomb/second
1 hp = 0.756 kW
1 N = 1 T·A·m
1 Pa = 1 N/m
2
Power = Joules/second =
I
2
R
=
IV
[watts
W
]
Quadratic
Equation:
x
b
b
ac
a
=

±

2
4
2
Kinetic Energy [J]
KE
mv
=
1
2
2
[Natural Log:
when
e
b
=
x
,
ln
x
=
b
]
m: 10
3
μ
: 10
6
n: 10
9
p: 10
12
f: 10
15
a: 10
18
Addition of Multiple Vectors:
r
r
r
r
R
A
B
C
=
+
+
Resultant = Sum of the vectors
r
r
r
r
R
A
B
C
x
x
x
x
=
+
+
x
component
A
A
x
=
cos
θ
r
r
r
r
R
A
B
C
y
y
y
y
=
+
+
y
component
A
A
y
=
sin
θ
R
R
R
x
y
=
+
2
2
Magnitude (length) of
R
q
R
y
x
R
R
=

tan
1
or
tan
q
R
y
x
R
R
=
Angle of the resultant
Multiplication of Vectors:
Cross Product
or Vector Product:
i
j
k
×
=
j
i
k
×
= 
i
i
×
=
0
Positive direction:
i
j
k
Dot Product
or Scalar Product:
i
j
⋅
=
0
i i
⋅
=
1
a b
⋅
=
ab
cos
q
k
i
j
Derivative of Vectors:
Velocity is the derivative of position with respect to time:
v
k
i
j
k
=
+
+
=
+
+
d
dt
x
y
z
dx
dt
dy
dt
dz
dt
(
)
i
j
Acceleration is the derivative of velocity with respect to
time:
a
k
i
j
k
=
+
+
=
+
+
d
dt
v
v
v
dv
dt
dv
dt
dv
dt
x
y
z
x
y
z
(
)
i
j
Rectangular Notation:
Z
R
jX
=
±
where
+
j
represents
inductive reactance and

j
represents capacitive reactance.
For example,
Z
j
=
+
8
6
Ω
means that a resistor of 8
Ω
is
in series with an inductive reactance of 6
Ω
.
Polar Notation:
Z = M
∠
q
, where
M
is the magnitude of the
reactance and
q
is the direction with respect to the
horizontal (pure resistance) axis.
For example, a resistor of
4
Ω
in series with a capacitor with a reactance of 3
Ω
would
be expressed as
5
∠
36.9°
Ω
.
In the descriptions above, impedance is used as an example.
Rectangular and Polar Notation can also be used to
express amperage, voltage, and power.
To convert from
rectangular to polar
notation:
Given:
X
 j
Y
(
careful with the sign before the ”j”)
Magnitude:
X
Y
M
2
2
+
=
Angle:
tan
θ =

Y
X
(negative sign carried over
from rectangular notation
in this example)
Note:
Due to the way the calculator works, if
X
is negative,
you must
add 180°
after taking the inverse tangent.
If the
result is greater than 180°, you may optionally subtract
360° to obtain the value closest to the reference angle.
To convert from
polar to rectangular
(j) notation:
Given:
M
∠
q
X
Value:
M
cos
θ
Y
(j) Value:
M
sin
θ
In conversions, the j value will have the
same sign as the
q
value for angles
having a magnitude < 180°.
Use rectangular notation when adding
and subtracting.
Use polar notation for multiplication and division.
Multiply in
polar notation by multiplying the magnitudes and adding
the angles.
Divide in polar notation by dividing the
magnitudes and subtracting the denominator angle from
the numerator angle.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview.
Sign up
to
access the rest of the document.
 Spring '10
 SEARCH
 Charge, Magnetism, Energy, Mass, Potential Energy, Neutron, Magnetic Field, Electric charge

Click to edit the document details