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Energy
Power
Formulas
Units and Variables
Problems
100
The ability to do work.
What is energy?
100
Relates work, energy and time.
What is power?
100
0.5mv²=
What is kinetic energy?
100
What is potential energy measured in?
Joules
100
What is the mechanical energy of an object whose kinetic energy is 120 J and its potential energy is 90 J?
210 J
200
Energy an object has by virtue of its motion.
What is kinetic energy?
200
What happens to power when time is doubled?
It is decreased by a factor of 2.
200
mgh=
What is potential energy?
200
What is kinetic energy measured in?
Joules
200
What is the potential energy of a lamp whose mass is 5kg and is 2.5 meters above the ground?
122.625 J
300
Energy an object has by virtue of its position.
What is potential energy?
300
Name something that uses power.
Light bulb, computer, motor, refrigerator, microwave...
300
E/∆t= or W/∆t=
What is power?
300
What is power measured in?
J/s or Watts
300
A runner whose mass is 60 kg travels at a speed of 5 m/s, what is his kinetic energy?
750 Joules
400
The sum of both kinetic and potential energies of an object.
What is mechanical energy?
400
What does power measure?
Measures how quickly energy is transferred and how quickly work is done.
400
Etotal= KE+U
What is mechanical energy?
400
What is the variable for potential energy?
U
400
Marie does 1500J of work going up a hill. If she goes up the hill in 3 seconds, what is her power output?
500 J/s
500
Energy is not created or destroyed, but it is transformed.
What is the law of conservation of energy?
500
What is a machine able to transfer if given enough time?
Any number of Joules.
500
KE_pt1+ U_pt1 = KE_pt2+ U_pt2
What is law of conservation of energy?
500
What is the variable for mechanical energy?
Etotal
500
A force of 480N pushes a wagon 8 meters in 16 seconds, what is the power?
240 J/s