# Hmwk 1 on Energy and Power ```University of California at Santa Cruz,
Homework #1 Energy and Power
Prof. Ali Shakouri
Oxana Pantchenko
Name: ____________________________
Student ID Number: _W_____________________
We can get energy from many different sources. Some are fuels that we extract by mining, and
others are natural energy flows that we can trap into.
1) Write down at least 5 sources of energy you can think of.
a.
b.
c.
d.
e.
2) What do you understand by the term “renewable energy”? Write down the things that
come to mind. Could you define it?
3) How does energy use affect the environment? Think of at least 3 issues.
4) Define energy in your own words? What are the units?
5) Define power in your own words? What are the units?
6) Convert the following energy quantities to the units shown.
a. Convert 1kJ to Wh
b. Convert 10,000 Btu to MJ
c. Convert 1kWh to MJ
7) How much energy (in kilowatt-hours) is consumed by a 600 W vacuum cleaner when
used for 30 minutes?
8) A clock radio consumes 240 Wh of electrical energy over a day. What is its power
consumption?
9) If a refrigerator motor uses 2kWh of electricity per day. It operates for an average of
only 20 minutes in the hour, what is the power rating of the fridge motor?
10) A sewing machine rated at 75W consumes 675 Wh of energy over a week. How long
was the machine used for over the week?
11) Think of 3 examples of energy consuming technology around your living area and
garage, and determine:
a. What form does the input energy take?
b. What form does the useful output energy take?
c. What forms do the energy losses take?
Item
Input Energy
Useful Output
Losses
Losses
Losses
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