Transcript Power and Work - Cleveland High School

POWER AND WORK
Mechanical
advantage,
efficiency, and
simple
machines
PHYSICAL SCIENCE QUESTIONS 11/5/14
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What is the standard unit for mass?
What is a standard unit for speed?
What is a unique distinctive for acceleration units?
What is the standard unit used to measure force?
What is the standard unit used to measure work?
_________ refers to the rate of work?
The standard unit for power is_______.
LESSON OBJECTIVE 11/5/14
Today we will be able to:
 Explain the relationships among work, power, and simple
machines both quantitatively and qualitatively.
NC Essential Standard PSc.3.1 .4
LESSON OVERVIEW 11/5/14
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Physical Science questions
EOC white board review
Egg drop completions
Power and Work power point
Work and Power Practice
PHYSICAL SCIENCE QUESTIONS 11/6/14
 In Science, work is done when a _________ acts on an object
in the direction the object moves.
 T or F A vertical force does work on an object that is moving
in a horizontal direction.
 What is the formula for work? Power?
 T or F You can increase power by doing a given amount of
work in a shorter period of time.
 T or F When you do less work in a given time period, the
power decreases.
 Work that is done on an object can be described as the force
acting on the object multiplied by the ___________ the object
moves.
LESSON OBJECTIVE 11/6/14
Today we will be able to:
Explain the relationships among work, power,
and simple machines both quantitatively and
qualitatively.
NC Essential Standard PSc.3.1.4
Define and determine ideal and actual
mechanical advantage
NC Essential Standard PSc.3.1.4
LESSON OVERVIEW 11/6/14
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Physical Science questions
Egg drop completions
Review of work and power
Mechanical Advantage ppt. and videos
Mechanical advantage worksheet
Work problems
PHYSICAL SCIENCE QUESTIONS 11/7/14
 T or F A machine can make work easier to do by changing the
size of the force needed, the direction of a force, or the
distance over which a force acts.
 The work done by a machine is always less than the work
done on a machine because of __________.
 The __________ is the amount of force exerted on a machine.
 Give an example of a machine that changes the direction of
an applied force.
 The number of times that the machine increases an input
force is the ____________ of a machine.
LESSON OBJECTIVE 11/7/14
Today we will be able to:
 Explain the relationships among work, power, and simple
machines both quantitatively and qualitatively.
NC Essential Standard PSc.3.1 .4
 Explain the relationship between work input and work output
for simple machines using the law of conservation of energy.
NC Essential Standard PSc. 3.1 .4
LESSON OVERVIEW 11/7/14
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Physical Science questions/vocabulary
Review of work and mechanical advantage
Simple machine lab
Mechanical advantage and ef ficiency formulas and
calculations
WORK PRACTICE 11/7/14
 How far will 490 J raise an 8 kg mass?
 How much work is done when an 25 N force moves a block?
 Calculate the ef ficiency of a machine with a work output of
240 j and a work input of 500 J
 Calculate the work input for a machine with a work output of
240J and an ef ficiency of 80 percent
PHYSICAL SCIENCE QUESTIONS
11/10/14
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What is the standard unit used to measure force?
What is the standard unit used to measure work?
_________ refers to the rate of work.
The standard unit for power is_______.
What is the formula to calculate the following?
 How much work can be done by a 120w motor in 7 sec.
 How far will 700J raise a block weighing 9N?
 How far will a 490J raise a 8Kg mass
LESSON OBJECTIVE 11/10/14
Today we will be able to:
 Explain the relationships among work, power, and simple
machines both quantitatively and qualitatively.
NC Essential Standard PSc.3.1 .4
 Explain the relationship between work input and work output
for simple machines using the law of conservation of energy.
NC Essential Standard PSc. 3.1 .4
LESSON OVERVIEW 11/10/14
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Physical Science questions
Review of simple machine lab
Word wise completion
Study guide completion
Calculation review
CALCULATIONS 11/10/14
 Which is more work pushing with 110 N over 10 m or lifting
10 kg 10m?
 What is the ef ficiency of a lever if you push 300N over 5m to
move 800N over 1m?
 If you put 800J into a machine but only get 400J out, how
ef ficient is the machine?
 How much work can be done by a 120W motor in 7 sec?