Work Done and Power Flashcards
(19 cards)
What is work done equivalent to?
Energy Transferred
How is work done calculated?
Force x distance moved in direction of force
What is energy?
The capacity of one object or system to do work (or cause a change) on another.
What is represented by the area under a force- distance graph?
Work done
What is the principle of conservation of energy?
The energy of a closed system always remains
constant. Energy can never be created or
destroyed, only transferred.
What form of energy is due to the motion of a
mass?
kinetic energy
What form of energy is due to the position of a
mass in a gravitational field?
gravitational potential energy
What form of energy is due to the bonds between atoms in a substance?
chemical energy
What form of energy is due to a reversible change in shape of an object?
elastic potential energy
What form of energy is due to the position of a
charge in an electric field?
electrical potential energy
What form of energy is due to the forces between protons and neutrons in an atom?
nuclear energy
What form of energy is due to randomly distributed potential and kinetic energies of the atoms within a
system?
thermal energy
What effect does friction have on the energy of a moving object?
Transfers kinetic energy primarily to thermal energy
Describe the energy transformations for an object sliding downhill at constant speed.
Describe the energy transformations for a vehicle travelling uphill at constant speed.
What is power?
Power is the rate at which work is done P = W/t
What is the derived unit of Power?
Watt (W)
What are the equivalent SI base units of the Watt?
Kgm2s-3
What is the equation
P = Fv used for?
The power developed by an object moving at
constant speed against a constant resistive force.
How is efficiency calculated?
(Useful output energy/total input energy) x 100
