is both a Thing and a Process

Transcription

1 ENERGY

2 = Matter + ENERGY

3 is both a Thing and a Process Matter HAS Energy. Energy is usually observable only during transfer. Allows WORK to be done. Matter is bottled-up energy.

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5 Energy is the capacity to dowork.

6 Hawkeye does work on his bow by drawing it. Staff Sgt. Joshua Miles, Marine Drum & Bugle Corps marketing chief, thrusts a weighted bar over his head during the first part of the Civilian Military Combine at Bryce Resort, Va., April 21, A force does when it acts on a body so that the body is displaced in the direction of the force. If the force does not displace the body, no work is done on it. The work is done on SOMETHING ELSE.

7 Work done on a body is defined as Force x distance W F d unit unit Work Work newton meter Nm J joule

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13 Twice as much work is done in lifting a load two stories instead of one story. Twice as much work is done in lifting two loads one story high versus lifting 1 load the same vertical distance.

14 Renatta Gass is out with her friends. Misfortune occurs and Renatta and her friends find themselves getting a workout. They apply a total force of 1080 N to push the car 218 m to the nearest fuel station. What is the work done on the car?

15 - The work done on an object by a net force equals the change in kinetic energy of the object K. E. W F d

16 The same amount of work is done in all three cases 3 m

17 Why do you run out of breath when running up stairs but not when walking up, when in fact the work done in both running and climbing up the stairs is the same?

18 - is equal to the amount of work done per time it takes to do it. Power work done time interval An engine with more power does not necessarily do more work it just does work faster.

19 unit Power joule second watt unit Power J s W The English system uses horsepower as a unit for power for engines. One horsepower is ¾ of a kilowatt.

20 Power Work time Force displacement time Power Force displacement time Power Force velocity A powerful machine is both Strong and fast!

21 Percentage of work put into a machine that is converted into useful work output. In equation form: Efficiency useful energy output total energy input

22 Efficiency CHECK YOUR ANSWER A certain machine is 30% efficient. This means the machine will convert A. 30% of the energy input to useful work 70% of the energy input will be wasted. B. 70% of the energy input to useful work 30% of the energy input will be wasted. C. Both of the above. D. None of the above Pearson Education, Inc.

23 Efficiency CHECK YOUR ANSWER A certain machine is 30% efficient. This means the machine will convert A. 30% of the energy input to useful work 70% of the energy input will be wasted. B. 70% of the energy input to useful work 30% of the energy input will be wasted. C. Both of the above. D. None of the above Pearson Education, Inc.

24 How many watts of power is needed to move an elevator containing 20 passengers, with a total mass of 1100 kg, three storeys up in 25 seconds if each storey is 5 meters high?

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26 Energy is the capacity to dowork.

27 Kinetic Energy energy of motion increases when object moves faster increases as mass of object increases Potential Energy energy of position stored energy increases as mass of object increases

28 Lt. I.M. Chisov of the former USSR was flying his Ilyushin 4 on a cold day in January 1942 when it was attacked by 12 German Messerschmitts. To escape his battered plane, Chisov bailed out at ft. Unfortunately, he lost consciousness and failed to deploy his parachute.

29 Kinetic Energy Potential Energy K. E. mv P. E. mgh (gravitational) 1 2 P. E. kx 2 (elastic)

30 What is the potential energy of a 2.0 kg book that is on a bookshelf 1.5 m above the floor?

31 A 7.00 kg bowling ball is moving in a bowling lane with a velocity of 5.00 m/s. What is the kinetic energy of the ball?

32 Energy is neither created nor destroyed, it is just transformed. The only thing that changes is the form in which it appears. E P. E. K. E for an isolated system

33 Energy transforms without net loss or net gain in the operation of a pile driver.

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37 - energy that is associated with temperature - increases as temperature increases

38 - energy stored in chemical bonds - released when chemicals are broken apart and new chemicals are formed

39 - can either be absorbed, reflected or transmitted. - when absorbed, an object gains energy and becomes warmer Natural Light sources Artificial Light Sources

40 - energy carried by an electric current - an electric device uses the electrical energy provided by the current flowing in the device.

41 - contained by the nucleus of an atom - can be transformed into other forms of energy - released during nuclear reactions; fission & fusion

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