Download Horsepower and Torque Worksheet

Exploring Robotics with Electronics: Presentations Worksheet
10: Horsepower and Torque
Name:
Date:
Class:
Teacher:
By the time students complete this section they will be able to:
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Know the definition of horsepower
Know the definition of torque
Understand how the size of a motor affects horsepower and torque
Understand how voltage and current affect Horsepower and torque
Understand concept of Current and Volts and how to determine the power requirements of a light
bulb and other common electrical items
Know the formula and be able to calculate Horsepower
Know the formula and be able to calculate Torque
Know the formula and be able to calculate Velocity
Understand the concept of Amps and be able to calculate Amps
Understand what factors are involved in the selection of motors, batteries, wire sizes, and electronic
components of hobby robots
Understand the RMF factor and be able to calculate it
Understand what an overcurrent protection device is and why it is used
Understand how voltage affects the size of wires used
Understand the concepts of velocity and acceleration in relation to motors
Be able to determine the power requirements of a motor given the HP and current
Points: (Your instructor will fill this in after reviewing the worksheet.)
Earned ____ out of ___ total points
Discussion Questions: Fill in the answers after each question.
1. What is the measurement used for defining the work done in a period of time?
2. What is horsepower? What else do you now know about horsepower?
3. What is the formula used for calculating horsepower?
4. What is torque? What else do you now know about torque?
5. What is the formula used for calculating torque?
6. If you have a robot arm that is 10 inches long, and a motor that lifts 100 ounces, how much
torque is this?
7. How does the size or RPMs of a motor affect horsepower and torque? As the motor RPMs
go up, what happens to horsepower? What happens to torque? As the motor RPMs go
down, what happens to horsepower? What happens to torque?
8. What is velocity?
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Exploring Robotics with Electronics: Presentations Worksheet
10: Horsepower and Torque
9. What is the formula used for calculating velocity for a hobby robot?
10. What is the velocity when the Diameter of the wheel is 5 and the RPM is 50?
11. What is current?
12. A 100 watt light bulb draws how much current at 100 volts of electricity?
13. How does current affect horsepower and torque?
14. How does the amount of current affect the size of wires used?
15. What is voltage?
16. How does voltage affect horsepower and torque?
17. How does the amount of voltage affect the size of wires used?
18. What factors are involved in the selection of motors, batteries, wire sizes, and electronic
components of hobby robots?
19. What is the RMF factor? What is the formula used to calculate it?
20. Suppose you want an 8 lb robot to have a speed of 6 ft/sec and accelerate at 4 ft/sec. Using
the formula mass x acceleration x velocity / (2 x PI), what is the approx. RMF factor of this
robot?
21. What is an overcurrent protection device and why is it used?
22. If a 1 HP motor operating at 120 volts is calculated as (746/120) = 6.21 amps, then you
would expect a 1.5 HP motor operating at 120 volts to require approx. how many amps?
23. Why is it important to know how many amps are used with a motor or any other electrical
device?
Enrichment Activities – Follow instructions provided by your instructor. Your instructor may assign one
or more of these to be completed.
1.
Explore more about Work, how it is measured and how energy is converted from one form to another in
physics.
a. Watch this video from NASA as a begin point.
http://www.youtube.com/watch?v=iCqm5uxc2dE
b.
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Questions to answer:
i. How is work measured?
ii. What is a joule? Give a couple of examples of what one joule represents.
iii. Define potential energy.
iv. Define kinetic energy.
v. Give an example of measuring work, kinetic energy, and potential energy.
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Exploring Robotics with Electronics: Presentations Worksheet
10: Horsepower and Torque
vi. Compare and contrast work and power in physics. How are each defined? How are they
measured? How are they similar? How are they different?
vii. What else do you want to know? Add your own questions
c. Write a report or generate a multimedia presentation about your findings. (See tips for
writing reports)
d. Include media components such as photos, sketches, diagrams, etc.
e. Include all your sources of information.
f. Summarize your findings.
g.
Optionally - share your report with the class.
2. Explore more about the relationships among current, voltage, resistance, and power.
a. Some potential questions to answer:
i. What are the symbols used for current, voltage, and resistance?
ii. What is Ohm’s Law?
iii. Who is Ohm’s Law named after?
iv. What is the formula used to calculate Ohm’s Law?
v. Draw a circuit diagram with a battery and a lamp and illustrate the amount of
current flowing using Ohm’s Law.
vi. What else do you want to know? Add your own questions
b. Write a report or generate a multimedia presentation about your findings. (See tips for
writing reports)
c. Include media components such as photos, sketches, diagrams, etc.
d. Include all your sources of information.
e. Summarize your findings.
f.
3.
Optionally - share your report with the class.
Koomey’s law states that the amount of computing power per joule (effectively per watt)
doubles every one and half years. Explore more about Koomey’s law and its inventor. Given
that computing power is measured in MIPS (millions of instructions per second), how can this
affect control systems that will be available in 10 to 20 years? Hint: start by finding the
computing power and watt requirements of a typical laptop, cell phone, tablet, and a
microprocessor board.
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