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19 terms

work

the product of the net force on an object and the distance through which the object is moved (force x distance)

joule

unit of work

power

the rate at which work is done

watt

joule per second. Unit of power

energy

the property of an object or system that enable it to do work

mechanical energy

energy due to the position or movement of something (kinetic and potential)

potential energy

energy that is stored and held at readiness

elastic potential energy

a stretched or compressed spring

chemical energy

any substance that can do work through chemical reactions

gravitational energy

energy due to elevated positions

weight x height

PE = mgh

weight x height

PE = mgh

kinetic energy

energy of motion

depends on mass and speed

equals half the mass x the square of the speed

KE = 1/2 mv^2

depends on mass and speed

equals half the mass x the square of the speed

KE = 1/2 mv^2

kinetic energy of a moving object

equal to the work required to bring it to its speed from rest, or the work the object can do while being brought to rest

net force x distance = KE

Fd = 1/2mv^2

net force x distance = KE

Fd = 1/2mv^2

work energy theorem

relationship between work and energy

whenever work is done energy changes

work = ^KE

whenever work is done energy changes

work = ^KE

law of conservation of energy

energy cannot be created or destroyed. it can be transformed from one form into another, but the total amount of energy never changes

machine

device used to multiply forces or change direction of forces

cannot put out more energy than is put in it

transfers energy to one place or another or transforms it from one form to another

cannot put out more energy than is put in it

transfers energy to one place or another or transforms it from one form to another

lever

simple machine made of a bar that turns about a fixed point

work input - work output

Fd(in) = Fd(out)

work input - work output

Fd(in) = Fd(out)

fulcrum

pivot point

pulley

kind of lever that can be used to change the direction of a force

efficiency

ratio of useful energy output to total energy input

useful work output/ total work input

actual mechanical advantage/ theoretical mechanical advantage

useful work output/ total work input

actual mechanical advantage/ theoretical mechanical advantage