review for test on energy
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Review for test on Energy. on. e. An object with a mass of 20 kg is moving 5 m/s . What is its kinetic energy?. 5 x 5 = 25 (velocity squared) 25 x 20 = 500 (mass x velocity) 500 / 2 = 250 j. 3 types of potential energy: Gravitational Elastic Chemical. - PowerPoint PPT PresentationTRANSCRIPT
Review for test on Energy
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An object with a mass of 20 kg is moving5 m/s. What is its kinetic energy?
5 x 5 = 25 (velocity squared)25 x 20 = 500 (mass x velocity)500 / 2 = 250 j
3 types of potential energy:
1. Gravitational2. Elastic3. Chemical
All energy is measured in Joules
GPE = weight (N) x height (m)Weight = mass (kg) x gravity (9.8 N)GPE can also be stated as mgh
A lift raises a 500 kg car 5 m off the ground.What is the potential energy given to thecar?
500 kg x 9.8 N = 4,940 (N) x 5 = 24,700 j
Potential energy is NotLost…it’s converted to KE
Seven forms of energy:
MRS CHENMechanical – Sum of PE + KERadiant – LightSoundChemical – batteries, foodHeat – Thermal ElectricalNuclear – happens in nucleus of atoms:
Fission – man made; Fusion - sun
What is the difference between Heat andTemperature?
Heat is the total energy of molecular motion in a substance while temperature is a measure of the average energy of molecular motion in a substance.
Floor heater
What is work?What is power?
Power is how quickly work is done; it is the rate, or speed, at which energy is transferred.
Work: using a force to move an object a distance. To do work, an object must move in the direction a force is applied.
SI unit is in joules
SI unit is in watts
Pre-AP only:
A lady ran for 3,000 seconds and her energyoutput is 270,000 joules. What was her average power?
Power = work (J) / time (s)
270,000 / 3,000 = 90 watts
Initial PE changes to Electrical energy
Know the difference between a renewableresource and a non-renewable resource.