Flashcards
OCR Gateway P3d
Cards in this deck (7)
- 1P3d - Work and Power.
- 2Weight an MassWeight is not the same as mass. Mass is a measure of how much stuff is in an object. Weight is a force acting on that stuff. Weight is the result of gravity.
- 3Calculating Weightweight = mass × gravitational field strength
- Weight is measured in newtons, N
- Mass is measured in kilograms, kg
- The gravitational field strength is measured in newtons per kilogram, N/kg
For example, the gravitational field strength is:
10 N/kg on Earth
1.6 N/kg on the Moon - 4Work is done when a force moves an object in the direction in which the force acts.The formula for work done:
Work Done = Force x Distance Moved (in the direction of the force)
Work done is measured in joules, J
Force is measured in newtons, N
Distance is measured in metres, m - 5Worked ExampleIf a person weighs 700N, the work he does against gravity when he jumps 0.8m is:
Work done = 700 x 0.8
= 560J - 6PowerPower is the rate at which work is done.
Power = work done ÷ time taken
Work done = power x time
Time taken = work done ÷ power
Power is measured in watts, W
Work done is measured in joules, J
Time is measured in seconds, s - 7CarsSome cars are more powerful than others. The power rating of a car depends on its engine size. More powerful cars have greater fuel consumption.
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- Flashcards on OCR Gateway P3d, created by Zaaaara on 28/05/2014.
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- Zaaaara
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