Names:
Pre-lab 3 Worksheet
1st Circuit: A Charging RC Circuit
Paste oscilloscope trace
of charging capacitor
here
Questions for 1st circuit:
Q1: For the RC circuit you built, what is the value of
the equation
V(t) Vo (1- e
t
Vo
in
?
RC )
Q2: From the know

Names:
Pre-lab 2 Worksheet
st
1 Circuit:
Paste
Questions for the 1st Circuit:
Q1: Compare the voltage differences across the 100 and the 220
resistors.
Q2: What can you say about the sum of the voltage differences
across the two resistors?
Q3: What can yo

EGR 241 Statics - Fall 2013
Dr. Matthew Rickard, Associate Professor
CBU College of Engineering
Sydney Harbor Bridge
http:/www.travlang.com/
Dr. Matthew Rickard
Associate Professor, CBU College of Engineering
BS, MS, PhD from UC Irvine in Mech & Aero Eng

Lenzs Law
There is an induced current in a closed, conducting loop if and
only if the magnetic flux through the loop is changing. The
direction of the induced current is such that the induced
magnetic field opposes the change in the flux.
i.e.
Changing ma

Electric Motor Rectangular Current Loop in a
Uniform Magnetic Field
Total Force on Loop = sum of Forces on each side
(
FB = I L ! B
)
FB = F1 + F2 + F3 + F4
"
"
two sides parallel (1 and 3) to field
and two perpendicular (2 and 4) to the field"
Electric M

Example 23.1
A flat loop of wire consisting of a single turn with area
8.00 cm2 is placed perpendicular to a magnetic field. The field
strength is uniformly increased from 0.500 T to 2.500 T in
1.00 s.
a.) What is the emf induced in the loop?
b.) If the c

Ampere s Law
More useful than Biot-Savart for cases of constant current
and regular geometry (symmetry)
! B ds =
0
I Through
- Integral is around a closed path (loop)
- Ithro is the total current passing through the loop
- 0 is the permeability of free s

Magnetic Force FB
Magnetic force on a moving charged particle is:
FB = q v ! B
where
q = electric charge
v = velocity
B = magnetic field
Units: Tesla (T)
1T = 1 N s C-1 m-1
Maximum and Minimum Force Values
FB = 0 (minimum) when
Sin = 0 = 0o or 180o
i.e.
B

Problem Solving Guide Network Analysis using
Kirchoffs Laws
1.) Draw circuit and label with all known quantities.
2.) Assign branch currents (if not already known).
3.) Apply the Junction Law to the junctions where
the branches meet.
4.) Apply the Loop La

Power Dissipated in/Radiated by a Resistor
Current flow in a resistor it gets warm
it radiates heat to its
environment
some electrical energy is
lost in the form of heat
Power Dissipated PR
= rate of heat loss due to current flow in the resistor
PR = I

The Elements of an Electric Circuit
Active Elements:
Battery source of Potential Difference
Resistor resistance to electric charge flow
Capacitor device to store electric charge
Inductor device used to produce a
magnetic field from charge flow.
(not shown

Moving Charged Particles in Electric Fields
Particle:
Mass m
Charge q
Coulombs Law :
Fe = q E
Newtons 3rd Law:
F = ma
!q"
a= # $ E
%m&
constant acceleration in
the direction of the electric
field.
Difficulties with Coulombs Law with Multiple and Extended

Discussion Question
The strength of electric force between two
electric charges depends on:
a.) the electric charge of the source charge
b.) the electric charge of the target charge
c.) the reciprocal of the distance between the
two charges
d.) a.) and b.

Electric Charge
Fundamental property of nature
two types
Positive (+)
Negative (-)
charge of the proton
charge of the electron
Basic Unit:
|electron charge|, e
electron
proton
neutron
qe = - e
qp = + e
qn = 0
e = 1.60 x 10-19 Coulombs
(C)
Ben Franklins Co