Homework 3 Unit 18 Problem 10, 12, 13(only b), 17, 18, 20 Unit 19 Problem 17, 20.

Slides:



Advertisements
Similar presentations
Chapter 12: Forces and Motion
Advertisements

Chapter 4: Making Sense of The Universe: Matter, Energy & Gravity
How to Study the Universe
Star Birth How do stars form? What is the maximum mass of a new star? What is the minimum mass of a new star?
The Beginning of Modern Astronomy
ASTR100 (Spring 2008) Introduction to Astronomy Newton’s Laws of Motion Prof. D.C. Richardson Sections
Chapter 5 Gravity. Describing motion Speed: Rate at which object moves example: 10 m/s Velocity: Speed and direction example: 10 m/s, due east Acceleration:
© 2010 Pearson Education, Inc. Chapter 4 Making Sense of the Universe: Understanding Motion, Energy, and Gravity.
Chapter 4 Making Sense of the Universe Understanding Motion, Energy, and Gravity.
Lecture Outline Chapter 4: Making Sense of the Universe Understanding Motion, Energy, and Gravity © 2015 Pearson Education, Inc.
Lecture Outline Chapter 4: Making Sense of the Universe Understanding Motion, Energy, and Gravity © 2015 Pearson Education, Inc.
If you hang a block of mass m from a spring with constant k and then pull it downwards by a distance H and let it bounce up and down, the mechanical energy.
Gravity. Review Question What are Kepler’s laws of planetary motion?
Physics 107, Fall From last time Gravity and centripetal acceleration Used to explore interesting questions like what is at the center of the galaxy.
Light Solar System Astronomy Chapter 4. Light & Matter Light tells us about matter Almost all the information we receive from space is in the form of.
PHYS 206 Matter and Light At least 95% of the celestial information we receive is in the form of light. Therefore we need to know what light is and where.
1 Tides We experience tides on Earth when the ocean level rises and falls. We experience 2 high tides and 2 low tides in a little over one day. But what.
© 2004 Pearson Education Inc., publishing as Addison-Wesley 5.1 Describing Motion: Examples from Daily Life Distinguish between speed, velocity, and acceleration.
This Set of Slides This set of slides covers finding distance in space, parallax review and limitations, some more physics (of light), the Inverse Square.
This Set of Slides This set of slides deals with the nature of light, how it’s created, some ways that it’s used in astronomy. Units covered: 21, 22, 24.
Chapter 5 Basic properties of light and matter. What can we learn by observing light from distant objects? How do we collect light from distant objects?
Units covered: , bit of 17, 19, and 20.
1 a little physics SESAME Astronomy Winter 2011 week 2.
PHY134 Introductory Astronomy Tides and Matter 1.
Universal Forces Section 3.5
© 2004 Pearson Education Inc., publishing as Addison-Wesley Orbital Energy and Escape Velocity orbital energy = kinetic energy + gravitational potential.
Surface Gravity Objects on the Moon weigh less than objects on Earth This is because surface gravity is less –The Moon has less mass than the Earth, so.
Comparative Planetology Comparative Planetology is the comparing and contrasting of different worlds to describe and categorize them Important Properties:
Chapter 2 Decoding the Hidden Messages in Starlight
Newton and Kepler. Newton’s Law of Gravitation The Law of Gravity Isaac Newton deduced that two particles of masses m 1 and m 2, separated by a distance.
Chapter 4: Newton and Universal Motion
Blackbody Radiation & Atomic Spectra. “Light” – From gamma-rays to radio waves The vast majority of information we have about astronomical objects comes.
Stellar Parallax & Electromagnetic Radiation. Stellar Parallax Given p in arcseconds (”), use d=1/p to calculate the distance which will be in units “parsecs”
© 2005 Pearson Education Inc., publishing as Addison-Wesley Correction in Exam 1 Date: Thursday Feb. 10 Updated Syllabus in website has the corrected date.
Copyright © 2009 Pearson Education, Inc. Chapter 4 Making Sense of the Universe: Understanding Motion, Energy, and Gravity.
Energy Energy is a property that enables something to do work
Properties of Light.
Homework #2  Due today at 6PM  Covers Chapters 1, 2, and 3  Estimated time to complete: 1 hour 10 minutes (so don’t wait until the last minute!)  Read.
PHYS 1621 Planetary Orbits Gravitational force between Sun and planets causes orbits with D being the planet’s distance from the Sun Force = G m Sun m.
Black Holes Escape velocity Event horizon Black hole parameters Falling into a black hole.
Laws of Motion and Energy Chapter Seven: Gravity and Space 7.1 Gravity 7.2 The Solar System 7.3 The Sun and the Stars.
Sir Isaac Newton Newton, as he appeared on the last day of his life, in 1727.
READING Unit 8, Unit 19, Unit 20, Unit 21, Unit 22, Unit 23.
Chapter 5: Light.
Units to read: 14, 15, 16, 17,18. Mass and Inertia Mass is described by the amount of matter an object contains. This is different from weight – weight.
Universal Gravitation.
1 Nature of Light Wave Properties Light is a self- propagating electro- magnetic wave –A time-varying electric field makes a magnetic field –A time-varying.
READING Unit 22, Unit 23, Unit 24, Unit 25. Homework 4 Unit 19, problem 5, problem 7 Unit 20, problem 6, problem 9 Unit 21, problem 9 Unit 22, problem.
The planets move in ellipses with the Sun at one focus. Conic section orbits are a natural outcome of the 1/d 2 nature of the gravitational force, in fact.
Describing Motion: Examples from Daily Life Distinguish between speed, velocity, and acceleration. What is the acceleration of gravity? How does the acceleration.
Homework 4 Unit 21 Problem 17, 18, 19 Unit 23 Problem 9, 10, 13, 15, 17, 18, 19, 20.
NATS From the Cosmos to Earth Billiard Balls.
Units 17, 18, 19, 20 Homework 3 is on the website of the course
© 2010 Pearson Education, Inc. Chapter 4 Making Sense of the Universe: Understanding Motion, Energy, and Gravity.
Atoms & Starlight (Chapter 6).
Chapter 2 Physical Science
A100 Movie Special Tuesday, March 23 Swain West 119 7:00 pm (153 minutes) Winner of several awards 20 activity points! BYOP (Bring Your Own Popcorn)
Electromagnetic Radiation, Atomic Structure & Spectra.
NATS From the Cosmos to Earth Light as a Wave For a wave, its speed: s = l x f But the speed of light is a constant, c. For light: l x f = c The.
Review Question What is retrograde motion?. Review Question Explain why the phases of Venus proved to Galileo that Venus must orbit the Sun when the Moon.
Universal Gravitation Does the moon stay at a certain distance from the Earth or is it falling toward the Earth? - the moon is actually falling around.
Motion and Energy. Motion What is Motion? Position is the location of an object. Motion is a change in position over time. Motion has two parts: distance.
Today: Go over Review Packet from last time Reviews 3 and 4 Homework: Review Packet.
© 2014 Pearson Education, Inc. Making Sense of the Universe: Understanding Motion, Energy, and Gravity.
Homework 2 Unit 14 Problems 17, 19 Unit 15. Problems 16, 17 Unit 16. Problems 12, 17 Unit 17, Problems 10, 19 Unit 12 Problems 10, 11, 16, 17, 18 Unit.
The Solar System Lesson2 Q & A
Lecture 3 Ast /4/07.
Chapter 4 Making Sense of the Universe:
Stars and Galaxies Lesson2 Q & A
Universal Gravitation
Presentation transcript:

Homework 3 Unit 18 Problem 10, 12, 13(only b), 17, 18, 20 Unit 19 Problem 17, 20

Escape Velocity is for more than just Rockets! The concept of escape velocity is useful for more than just rockets! It helps determine which planets have an atmosphere, and which don ’ t –Object with a smaller mass (such as the Moon, or Mercury) have a low escape velocity. Gas particles near the planet can escape easily, so these bodies don ’ t have much of an atmosphere. –Planets with a high mass, such as Jupiter, have very high escape velocities, so gas particles have a difficult time escaping. Massive planets tend to have thick atmospheres.

The Origin of Tides The Moon exerts a gravitational force on the Earth, stretching it! –Water responds to this pull by flowing towards the source of the force, creating tidal bulges both beneath the Moon and on the opposite side of the Earth

High and Low Tides As the Earth rotates beneath the Moon, the surface of the Earth experiences high and low tides

The Sun creates tides, too! The Sun is much more massive than the Moon, so one might think it would create far larger tides! The Sun is much farther away, so its tidal forces are smaller, but still noticeable! When the Sun and the Moon line up, higher tides, call “ spring tides ” are formed When the Sun and the Moon are at right angles to each other, their tidal forces work against each other, and smaller “ neap tides ” result.

The Conservation of Energy The energy in a closed system may change form, but the total amount of energy does not change as a result of any process

Kinetic Energy is simply the energy of motion Both mass (m) and velocity (V) contribute to kinetic energy Imagine catching a thrown ball. –If the ball is thrown gently, it hits your hand with very little pain –If the ball is thrown very hard, it hurts to catch! Kinetic Energy

Thermal Energy Thermal energy is the energy associated with heat It is the energy of the random motion of individual atoms within an object. What you perceive as heat on a stovetop is the energy of the individual atoms in the heating element striking your finger

Potential Energy You can think of potential energy as stored energy, energy ready to be converted into another form Gravitational potential energy is the energy stored as a result of an object being lifted upwards against the pull of gravity Potential energy is released when the object is put into motion, or allowed to fall.

Conversion of Potential Energy Example: –A bowling ball is lifted from the floor onto a table Converts chemical energy in your muscles into potential energy of the ball –The ball is allowed to roll off the table As the ball accelerates downward toward the floor, gravitational potential energy is converted to kinetic energy –When the ball hits the floor, it makes a sound, and the floor trembles Kinetic energy of the ball is converted into sound energy in the air and floor, as well as some heat energy as the atoms in the floor and ball get knocked around by the impact

Definition of Angular Momentum Angular momentum is the rotational equivalent of inertia Can be expressed mathematically as the product of the objects mass, rotational velocity, and radius If no external forces are acting on an object, then its angular momentum is conserved, or a constant:

Conservation of Angular Momentum Since angular momentum is conserved, if either the mass, size or speed of a spinning object changes, the other values must change to maintain the same value of momentum –As a spinning figure skater pulls her arms inward, she changes her value of r in angular momentum. –Mass cannot increase, so her rotational speed must increase to maintain a constant angular momentum Works for stars, planets orbiting the Sun, and satellites orbiting the Earth, too!

The Nature of Light As a wave… –A small disturbance in an electric field creates a small magnetic field, which in turn creates a small electric field, and so on… Light propagates itself “ by its bootstraps! ” –Light waves can interfere with other light waves, canceling or amplifying them! –The color of light is determined by its wavelength. As a particle… –Particles of light (photons) travel through space. –These photons have very specific energies. that is, light is quantized. –Photons strike your eye (or other sensors) like a very small bullet, and are detected. Light is radiant energy. Travels very fast – 300,000 km/sec! Can be described either as a wave or as a particle traveling through space.

The Effect of Distance on Light Light from distant objects seems very dim –Why? Is it because the photons are losing energy? –No – the light is simply spreading out as it travels from its source to its destination –The farther from the source you are, the dimmer the light seems –We say that the object ’ s brightness, or amount of light received from a source, is decreasing This is an inverse-square law – the brightness decreases as the square of the distance (d) from the source

The Nature of Matter The atom has a nucleus at its center containing protons and neutrons Outside of the nucleus, electrons whiz around in clouds called orbitals –Electrons can also be described using wave or particle models –Electron orbitals are quantized – that is, they exist only at very particular energies –The lowest energy orbital is called the ground state, one electron wave long To move an electron from one orbital to the next higher one, a specific amount of energy must be added. Likewise, a specific amount of energy must be released for an electron to move to a lower orbital These are called electronic transitions

The Chemical Elements The number of protons (atomic number) in a nucleus determines what element a substance is. Each element has a number of electrons equal to the number of protons The electron orbitals are different for each element, and the energy differences between the orbitals are unique as well. This means that if we can detect the energy emitted or absorbed by an atom during an electronic transition, we can tell what element the atom belongs to, even from millions of light years away!

Measuring Temperature It is useful to think of temperature in a slightly different way than we are accustomed to –Temperature is a measure of the motion of atoms in an object –Objects with low temperatures have atoms that are not moving much –Objects with high temperatures have atoms that are moving around very rapidly The Kelvin temperature scale was designed to reflect this –0  K is absolute zero –the atoms in an object are not moving at all!

Results of More Collisions Additional collisions mean that more photons are emitted, so the object gets brighter Additional hard collisions means that more photons of higher energy are emitted, so the object appears to shift in color from red, to orange, to yellow, and so on. Of course we have a Law to describe this…

Wien’s Law and the Stefan-Boltzmann Law Wien ’ s Law: –Hotter bodies emit more strongly at shorter wavelengths SB Law: –The luminosity of a hot body rises rapidly with temperature