Download (Kelvin) emits radiation in vacuum at a rate in W

UNIVERSITY OF MASSACHUSETTS DARTMOUTH
COLLEGE OF ENGINEERING
EGR 101 INTRODUCTION TO ENGINEERING I
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This assignment is due Thursday, October 29, 2009.
Use engineering papers.
Show all of your steps.
Present your work neatly and clearly.
Box your final answers.
Problem 1
Problem 4 in Chapter 9 on p. 281.
 Calculate the period in ms.
 Calculate frequency in kHz.
 Express the signal as VS  t   Vpk sin t  if this is a voltage source. On the scope
the voltage scale is 5 V/div.
Problem 2
Consider a signal whose angular frequency is 500 x 103 rad/sec.
 Calculate the frequency in kHz.
 Calculate the period in  s .
Problem 3
Consider an alternating voltage source VS with an amplitude of 50 V and a period of 10
s .
 Express the source voltage as VS  t   Vpk sin t  by identifying V pk and  .
 Determine V1, pk and V2, pk across resistors R1 and R2 by the voltage divider
method.
Problem 4
Consider the triangular voltage signal (V) as a function of time in ms.
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Identify the points in time where the function is discontinuous.
What is the period of the signal?
What is the voltage as t approaches 0.2 ms from the left?
What is the voltage as t approaches 0.2 ms from the right?
Plot the derivative of this function in the interval 0  t  0.8 ms .
What is the derivative at t = 0.2 ms?
Problem 5
In class, you learned that an alternating voltage can be generated by turning a wire blob
between two magnets. Please visit the following link for an animation:
http://www.physclips.unsw.edu.au/jw/electricmotors.html#alternator
You may see the wire already turning when you open the page. However, you can push
the play button to repeat the animation.
 Use your watch or a timer, click the play button and time in seconds how long it
takes the wire to execute two rotations. Repeat your experiment 10 times.
 Calculate the mean value based on your 10 data points.
rad
 Calculate the wire angular speed  in
and rpm based on your average time.
s
 Calculate the frequency of the voltage in Hz and the period in s.