MAE 2055: Mechetronics I
Mechanical and Aerospace Engineering
Summer 2014
Homework 1
1)
The source voltage in the circuit above is
( )
(
)
a) Determine an expression for the current flowing through the resistor, ( ).
b) Using MATLAB plot two full periods of both ( ) and ( ). If you are unfamiliar with using
MATLAB, make use of the resources provided on the MATLAB page of the course website.
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Plot the waveforms on two separate subplots, one above the other.
Label the axes, including units.
Include a title on the plots.
Write your code in an m-file and submit a copy with your homework.
2)
a) What is the value of resistor
?
b) Calculate , the current through resistor
.
c) Calculate , the power associated with resistor
power supplied or dissipated by the resistor?
d) Calculate
, the power associated with
e) What is the power,
by the source?
. Is
. Pay attention to the sign of your result. Is
power supplied or dissipated by
?
, associated with the voltage source? Is power supplied or dissipated
3) The following circuit represents a flashlight with a single bulb and two D-cell alkaline batteries. At
operating conditions the light bulb has a resistance of 10Ω.
a) When the switch is closed, how much current flows through the light bulb?
b) What is the power associated with the bulb? Is power supplied or dissipated?
c) What is the total power associated with the batteries? Is power supplied or dissipated?
d) If the capacity of the batteries is 15,000 mAh, approximately how long will the batteries last?
e) What are some factors that could cause your calculation in d) to be inaccurate?