Energy Conversion, Electromagnetism, and Kepler's Laws Physics Review

Energy

ability to do work

How is work done?

when a force moves an object over a distance, energy is transferred

Conservation of Energy

the principle stating that energy cannot be created or destroyed, only transformed from one form to another

Open System

system that exchanges matter and energy with its surrounding environment

Isolated System

system that does not exchange matter or energy with its surrounding environment

Translational Kinetic Energy

energy due to changing position (ke_trans = (1/2)mv²)

Rotational Kinetic Energy

kinetic energy of a spinning object (ke_rot = (1/2)Iw²)

Gravitational Potential Energy

stored energy due to the gravitational force between objects

GPE equals to

kinetic energy

Mechanical Energy

sum of the potential energy and kinetic energy of an object; changes when work is done on the object

Elastic Potential Energy

stored energy due to an object’s change in shape (bowstring, rubber balls, rubber bands)

Chemical Energy

released from burning fossile fuels during digestion

Nuclear Energy

released when the structure of an atom’s nucleus changes

Thermal Energy

sum of the ke and pe of the particles in a system

Radiant Energy

carried by electromagnetic waves

Electrical Energy

associated with charged particles

Light Energy

form of energy that exhibits wavelike behavior as it travels through space; part of the elctromagnetic spectrum

Sound Energy

form of energy that is made by vibrations traveling as waves and requires a medium in order to travel

Microscopic Energy

energy found at the atomic and molecular level

Macroscopic Energy

energy that can be seen with the naked eye

Grounding

removing excess charge by connecting an object to Earth

Charging by Conduction

charging a neutral object by touching it

Charging by Induction

charging a neutral object by bringing a charged object near it

North Pole of a Magnet

positive; field goes out

South Pole of a Magnet

negative; field comes in

Joules (J)

unit that work and energy is typically measured in

Work is done when a

force moves an object through a distance

Reference Level

the height used to which an object has risen is determined, where GPE is defined as 0

Calculation of KE_rot

using the system’s moment of inertia (I) and its angular velocity (w)

Gravitational Force

a force of attraction between masses

Gravitation

a force of attraction exerted by each particle of matter in the universe on every other particle

Gravitational Field

the region of space surrounding a body in which another body experiences a force of gravitational attraction

Field Forces

forces that act over a distance, such as gravity

Newton’s Law of Universal Gravitation

law stating that every piece of matter is attracted to every piece of matter

force is directly proportional to their masses but inversely proportional to the square distance between them

Electrostatics

study of electric charges that can be collected and held in one place

2 Types of Electric Charges

positive charges and negative charges

Two objects with the same charges always

repel each other

Two objects with the opposite charges always

attract each other

Electric Force

the interaction between a charged particle and an electromagnetic field of between two charged particles

Coulomb (C)

the SI unit of electric charge, equal to the quantity of electricity conveyed in one second by a current of one ampere

The Charge on a Single Proton

+1.602 × 10^-19; that is the magnitude of the charge of a proton is equal to the magnitude of the charge of an electron

The Charge on a Single Electron

-1.602 × 10^-19

Magnitude of a Charge on a Single Proton

referred to as the elementary proton

Charge on One Coulomb

6.24 × 10¹⁸

Elipse

a special curve in which the sum of distances from every point on the curve to two other points; following the path of an oval shape

The Law of Ellipse

law that states that all planets move in an elliptical orbit around the sun. with the center of the sun being located at one focus

Orbit

a curved path by a satellite as it revolves around an object space

Focus (Foci)

a point in the ellipse that helps determine the shape

Eccentricity

the measurement of how an elliptical orbit deviates from a perfect circular orbit

Major Axis

a line along the widest part of an ellipse

Semi Major Axis

one-half of the major axis, which runs from the center, through a focus, and to the perimeter; essentially, it is the radius of an orbit at the orbit’s two most distant points

Aphelion

the point of an orbit where the celestial body is farthest from the Sun

Perihelion

the point closest to the Sun in the orbit of a celestial body

Astronomical Unit

a measurement equal to the distance between Earth and the Sun, a distance of about 150 million kilometers (93 million miles)

The Law of Equal Areas

the law that describes the speed of the planets that orbit the Sun

Orbital Period

the time a given astronomical object takes to complete one orbit around another object

The Law of Harmonies

the law that describes the size of a planet’s orbit

the ratio of the squares of the periods at any 2 planets to the ratio of the cubes of the average distances from the sun

Kepler’s 1st Law

all planets move in elliptical orbits around the Sun, with the Sun at one focus

Kepler’s 2nd Law

a line connecting a planet to the Sun sweeps out equal areas in equal times

Kepler’s 3rd Law

the square of a planet's orbital period is proportional to the cube of the average distance from the Sun

Attractive Force

a force that moves objects closer

Repulsive Force

the force that acts between bodies of like electric charge or magnetic polarity, tending to separating them

Circuit

a closed loop of conductors through which an electric current can flow

Current

the flow of an electrical charge through an object or medium

Voltage

the difference in potential electrical between 2 points

Electric Field

a property of the space around a charged object that exerts forces on other charged objects

Electric Field Lines

indicates the direction of the force due to the electric field on a positive test charge

What does the spacing between the lines indicates?

it indicates the electric field’s strength; a stronger field result in lines that are spaced more closely

Where are electric field lines directed towards?

the lines are directed towards negative charges and away from positive charges

What happens when two neutral charges are rubbed together?

each can become charged

What happens when rubber shoes are rubbed on a wool rug?

electrons are removed form the atoms in the wool and transferred to the shoes

Metals are (bad/good) conductors

good; because at least one electron on each atom can be removed easily