U4 - Energy - Work - Simple Machines

Kinetic Energy

object that has energy because it is in motion

energy

ability to cause change

types of kinetic energy

radiant, thermal motion, sound, energy

kinetic energy formula

KE = 1/2mv²

radiant energy

carried by electromagnetic waves

electromagnetic waves

radio, microwave, infrared, visible (ROYGBIV), ultraviolet (UV), X-ray, gamma ray

thermal energy

sum of kinetic energy and potential energy of the particles that make up the object

geothermal energy

energy produced from near surface molten rock

sound energy

carried by sound waves

electric energy

form of kinetic energy that an electric current carries

seismic energy

transferred by waves moving through the ground

potential energy

stored energy that depends on the interactions of objects, particles, or atoms

Types of potential energy

gravitational, elastic, chemical nuclear

gravitational potential energy

type of potential energy stored in an object that depends on it’s mass and its height above the surface of the Earth

gravitational potential energy formula

GPE = mgh

chemical energy

stored in and released from the bonds between atoms

nuclear energy

stored in and released from the nucleus of an atom through fission (splitting atoms) by humans or fusion (Uniting atoms) in the high temperatures and pressure found in the Sun

mechanical energy

sum of potential energy and kinetic energy in a system of objects

energy transformations

conversation of energy from one form to another

law of conservation of energy

states that energy can be transformed from one form to another, but cannot be created or destroyed

work

transfer of energy that occurs when a force makes an object moves in the direction of the force while the force acts on the object

simple machine

does work through one movement that changes the direction or the amount of force required to preform the task

level

pivots around a fixed point

inclined plane

flat, slopped surface

screw

inclined plane wrapped around a cylinder

wedge

inclined plane that moves

wheel and axle

shaft attached to a wheel so that both rotate together

gear

toothed wheel used to transfer rotary motion and torque through interlocking teeth

pulley

grooved wheel with a rope or cable wrapped around it

output force (resistance force)

the force exerted on a object by a machine

input force (effort force)

the force you exert on a machine

Ideal Mechanical Advantage (IMA)

the mechanical advantage of a machine in the absence of friction

actual mechanical advantage (AMA)

the mechanical advantage of a machine in a real situation

AMA equation

output force/ input force

complex machine

2 or more simple machines working together

work equation

W = Fd, work = force x distance

Joule

unit of energy AND work

power

the rate of which work is done

Watt

standard metric unit of power; horsepower is equivalent to 750 of these

power formula

P=work/time (or P=Force*velocity)

efficiency

the machine of how much work put into the machine is changed into useful output work; note that it is never 100% because some of the work is transformed into wasteful thermal energy

efficiency equation

(Output force/input force)*100%