1. Resistance (of a wire)
Where R is resistance in Ohms, L the length, and A the cross sectional area

2. Diagramming circuits

3. Ohm’s Law Mnemonic P = IV where 1000W = 1kiloWatt 1kW * 1 hour = 1kWh
The cost of 1 kWh is $0.134 in this area.
kW * hours * $/kWh = Cost for one hour of operation
P = IV where
P = Power (in Watts, the rate at which energy is consumed)
I = Current
V = Voltage
Typical household voltage is 120V.

4. Important equations for Electricity
Series Circuits
VT = V1 + V2 + V3 + …
V = Voltage (Volts)
I = Current (Amps)
R = Resistance (Ohms)
RT = R1 + R2 + R3 + …
IT = I1 = I2 = I3 = …
In a series electric circuit all of the electrons must flow through the same elements.
In a series circuit each resistor adds to the total resistance.
In a parallel electric circuit electrons may flow through different circuit elements.
In a parallel circuit each resistor provides another way for electrons to flow.
Parallel Circuits
VT = V1 = V2 = V3 = …
RT < R1, R2, R3, …
IT = I1 + I2 + I3 + …

5. Tell me about heart bypassess…

6. A V V V V A V V A V V Series Circuit I4 = VT = V1 + V2 + V3 + … R7 =
RT = R1 + R2 + R3 + … +
R8 = 2
V6 =
V8 = V V A
I5 =
V9 = 5
R9 =
IT = I1 = I2 = I3 = … V V A
I6 =
R10 = 4 V V
V10 =4

7. V V A Parallel Circuit R1 = 100 Ohms VT = 120V R2 = 200 Ohms V1 = R3 =
RT =
V3 =
V2, I2
V3, I3 V V R1
V1, I1 R2 R3 A IT
IT =
I1 =
I2 =
I3 = 0.8A

8. KWH
Utility
$/kWh CH
$0.134
Cost / day = kW * Hours/day * $/kWh
Item
Watts
kW (1000W)
Current
Hours/day
Cost / day
Cost / year
Total
P = IV where P is power in Watts, I is current (in Amps), and V is voltage. Assume V = 120V

9. Ideal Gas Law: PV = nRT As pressure increases …
As the number of atoms increases …
As the temperature increases …
As the volume changes …

10. Pendular Motion The period of the simple pendulum is given by
Where T is the period, L is the length of the pendulum, and g is the acceleration due to gravity.
T is a function of length. It has a weak dependence on the angular displacement and should not be affected by the mass.

11. Review: Key characteristics of waves
Amplitude: The height of the wave from node to antinode (transverse waves), or the distance between compression and rarefaction in a in a compressive wave. Measured in units describing the wave
Wavelength: The distance traversed by a full cycle of the wave
Node: The “zero point” of the wave
Antinode: The extreme point of the wave (max or min amplitude)
Period: The time between successive waves
Frequency: The rate of occurrence of the wave (in Hertz or cycles / second)
Antinode
Node
Amplitude
Wavelength

12. Speed of Waves
The relationship between wave speed, wavelength, and frequency is simple
For a given temperature, pressure, material, etc.
v = fl,
where v is the speed, f is the frequency, and lambda is the wavelength.