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Formulas
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Energy
Heat
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100
Formula for Work:
Work (J) = Force (N) x Displacement (m)
100
What is my work if my force is 25N and the displacement is 35m?
875 J
100
What does the Law of Conservation of Energy state?
Energy cannot be created nor destroyed, only transformed.
100
What are the three types of heat transfer?
Conduction, convection, and radiation
100
What's the difference between a conductor and an insulator?
Conductor- thermal energy moves easily. Insulator- thermal energy does not move easily.
200
Formula for Power
Power (w) = Work (J) divided by Time (s)
200
What is the power if work is 300J and the time is 35 seconds?
8.6 watts
200
What is the difference between work and power?
Time affects power but has no affect on work.
200
What is the Kelvin Scale based on?
Absolute Zero- when theoretically the molecules in an object are not moving at all (zero kinetic energy)
200
When you hold a cup of coffee, is heat transferred from the coffee to your hand or is the coolness of your hand transferred to the coffee?
Heat transferred from the coffee to your hand- second law of thermodynamics!
300
Formula for Potential Energy:
Potential Energy (J) = Mass x Gravity x Height
300
What is the GPE with a mass of 82kg and height of 2m?
1,607 J
300
During an energy transformation from potential to kinetic energy, sometimes energy is lost due to friction. That "lost" energy is actually just transformed into...
thermal energy
300
What is temperature in terms of kinetic energy?
Temperature is the average amount of kinetic energy of all the particles that make up an object (how fast are they moving? The faster they're moving, the greater the kinetic energy, therefore, the greater the temperature).
300
How many sig figs: 1.002
4 sig figs
400
Kinetic Energy Equation
Kinetic Energy (J) = 1/2 x mass x velocity sqaured
400
What is the KE of a cat who's mass is 1.4kg and is running with a speed of 22.5m/s?
354.4 J
400
What are the three different types of systems?
Open, Closed, Isolated
400
What does the first law of thermodynamics state?
The total energy used in any process is conserved, whether that energy is transferred as a result of work, heat, or both. (Therefore, there are two ways to increase the temperature of a system- either add heat, do work, or do both)
400
What's the difference between the kinetic energy of the particles in Cup A and Cup B when Cup A has a higher temperature?
Cup A's particles are moving faster than the particles in Cup B.
500
Specific Heat Formula
Thermal Energy (J) = mass x specific heat x temperature change
500
Change 56 degrees Fahrenheit to Celsius.
13.3 Degrees Celsius
500
Give an example of an energy transformation from kinetic energy to potential energy.
Answers will vary- the object should be in motion and slowing down.
500
What does the second law of thermodynamics state?
The energy transferred as heat always moves from an object at a higher temperature to an object at a lower temperature.
500
What do we call the sum of an object's kinetic and potential energies?
Mechanical Energy