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41 Cards in this Set
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What is the formula for a joule?

A joule equals one newton x one meter
(N x m) 

What is the result of a force moving an object over a distance?

Work


What are you doing when you push, lift, or throw and object?

Work


What is the formula for work?

W = F x D


What is "F" ?

F = force acting on an object


What is "d"?

d = distance the object moves in the direction of the force


What is the unit of measurement for work in the metric system?

Joule


A joule equals the force of what?

A newton moving an object 1 meter


Who is the joule named after?

James Prescott Joule
19th century English physicist who studied transformation 

What is the work done when a 500N student climbs a rope for 5 meters?

W = F x D
W = 500n x 5m W = 2500 x m W = 2500J 

Is a horse doing work when it stands with a rider sitting on it?

No  because the horse is not pushing, lifting, or throwing. No force is acting over a distance.


When you climb to the top of rope and hang there, are you doing work?

No  not moving your body over a distance


What is the amount of work done during a given period of time

Power


How is power measured?

Power is measured in watts (W)


A watt is equal to how many joule?

1 W = joule per second
(J/s) 

How many joules is a 100W lightbulb using?

100 joules per second


A kilowatt (kW) is equal to how many watts?

1 kW = 1000 W


One horsepower is equal to how many watts?

1 hp = 0.746W


Horsepower is used to describe what?

The power of engines


Who described the power of a steam engine?

James Watt
A Scottish engineer described the power used to a horse to pull a heavy load 

What is the equation of power?

Power = Work/Time
P = w/t 

What is the power of a motor that does 2000 J of work in a 10 second period?

P = w/t
P = 2000J/10s P = 200J/S P = 200W 

If the power of a motor is 200W, what is the horsepower of the motor?

200W / 746W = .26hp


Is throwing a football 20 yards work or not?

Yes


You push against a wall until you are tired. Is this work?

No


Your study these flashcards all day long for this stupid test. Is this work?

No


You push your brother out of your way to sit down  are you working?

Yes


How much work is done when a 175 N man pulls a sled 500m?

W = F x D
W = 175 x 500 W = 87,500J 

A 98 N woman carries her baby 12 m. How much work is done?

No work


What is the work done when a 1000N person jumps 1 meter into the air?

W = F x D
W = 1000 N x 1m W = 1000 x m W = 1000J 

A 100W lightbulb has more what than a 60W bulb?
a. power b. joule c. watt d. force 
Power


What is the amount of work per unit of time?

Power


What is the reate at which work is done?

Power


When power increases, does the rate of work increase or decrease

Increase


How much work does a 150w lightbulb do?

150 joules


Power is force x distance and divided by what?

Time


When time and force remain the same, power is increased when what increases?

Distance


What is the equation for power?

P = Work/Time


Power is measured in what?

watts


One horsepower equals how many watts?

746 watts


A pencil sharpener uses 1,000 joules in 10 seconds. What is the power usage?

P = 1,000j /10s
P = 100j / s P = 100W 