energy conversion
the transfer of energy to an object by using a force that causes the object to move in the
elastic potential energy
energy stored inside elastic
photosynthesis
when plants convert the sun's light energy into chemical energy
potential types
Chemical, Mechanic, Nuclear, and Gravitational
kinetic types
Thermal, Kinetic, Sound, LIght, and ELectric
GPE
weight * height
kinetic
mv�/2
mechanical energy
potential energy + kinetic energy
Examples
chemical in food used as kinetic when digested and people do activities
Machines can
convert energy into different forms
Elastic potential energy
potential energy in elastic
energy
the capacity to do work
kinetic energy
the energy of an object that is due to the object's motion
mechanical energy
the energy that an object has because of the position, shape, or condition of the object
potential energy
the amount of work an object can do because of the object's kinetic and potential energies
energy
measured in joules
kinetic energy
mv�/2
gravitational potential energy
weight * height
gpe
work force * distance
mechanical energy
kinetic energy + potential energy
Thermal energy
all of kinetic energy due to random motion of the particles that make up an object
Chemical energy
energy of a compound that changes as its atoms are rearranged
Sound energy
energy cuased by an object's vibrations
Nuclear energy
energy that comes from changes in the nucleus of an atom
Electrical energy
energy of moving electrons
light energy
energy produced by the vibrations of electrically charged particles
fusion
when two nuclei are fused together
fission
when a nucleus is split apart
the greater the temperature
the faster the particles move
the lesser the temperature
the slower the particles move
lever
a simple machine that consists of a bar that pivots at a fixed point called a fulcrum
pulley
a simple machine that consists of a wheel over which a rope, chain, or wire passes
wheel and axle
a simple machine consisting of two circular objects of different sizes; the wheel is the larger of the two circular objects
inclined plane
a simple machine that is a straight, slanted surface, which facilitates the raising of loads; a ramp
wedge
a simple machine that is made up of two inclined planes and that moves; often used for cutting
screw
a simple machine that consists of an inclined plane wrapped around a cylinder
compound machine
a machine made of more than one simple machine
fulcrum
a fixed point on which a lever pivots
block and tackle
When a fixed pulley and movable pulley are used together
radius
the distance from the center to the edge
work
the transfer of energy to an object by using a force that causes the object to move in the direction of the force
joule
the rate at which work is done or energy is transformed
power
the unit used to express energy; equivalent to the amount of work done by a force of 1 N acting through a distance of 1 m in the direction of the force (symbol, J)
watt
the unit used to express power; equivalent to a joule per second (symbol, W)
Work
W=f x d force x distance
power
P=w/t
watt
one Joule per second j/s
machine
a device that helps do work by either overcoming a force or changing the direction of the applied force
work input
the work done on a machine; the product of the input force and the distance through which the force is exerted
work output
the work done by a machine; the product of the output force and the distance through which the force is exerted
mechanical advantage
a number that tells how many times a machine multiplies force
mechanical efficiency
a quantity, usually expressed as a percentage, that measures the ratio of work output to work input in a machine
common machines
chopsticks, lever, wheelchair, and scissors
work increase or decreases
according to distance traveled and force applied
machines change
the size of force and distance applied
mechanical advatage
output force/input force
mechanical efficiency
work output/work input * 100
ideal machine
a machine that has 100% mechanical efficiency
energy
the capacity to do work
kinetic energy
the energy of an object that is due to the object's motion
potential energy
energy stored due to an object's position or arrangement
mechanical energy
the amount of work an object can do because of the object's kinetic and potential energies