physics: it explains everything. what is physics? physics is the study of matter and energy it deals...
TRANSCRIPT
![Page 1: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/1.jpg)
Physics:
It Explains Everything
![Page 2: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/2.jpg)
What is physics?
• Physics is the study of matter and energy
• It deals with how the two interact and interact with each other
• Chemistry is the study of matter but physics deals with the energy involved
![Page 3: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/3.jpg)
You do physics every day
• Whenever you do anything, you’re doing physics
• Whenever you, as a body composed of matter, interact with another body of matter, you’re doing physics.
![Page 4: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/4.jpg)
Here are some examples
![Page 5: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/5.jpg)
We Will Keep it Simple
• Physics has many sub-divisions• Such as..• Kinematics
• cosmology
• quantum physics
• theoretical physics
• Condensed Matter Physics
• Atomic, molecular, and optical (AMO) Physics
• High Energy Physics
• Astrophysics
• Applied Physics
![Page 6: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/6.jpg)
We Will stick to Kinematics
• This deals with motion on the large scale
• So we’ll be discussing things such as force, mass, weight, acceleration, Newton’s Laws, simple machines, speed, velocity, energy and energy transfer
• All of these topics should be familiar to you
• Let’s start with an easy one
![Page 7: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/7.jpg)
What is a force?
• It is a push or a pull on an object (f =ma)
• there are only four forces in the known universe– gravity– electromagnetic force– strong nuclear force– weak nuclear force
• all forces that we see in nature are one of these four
![Page 8: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/8.jpg)
Gravity
• This is the force of attraction between two objects
• It is determined by the masses of the two objects and the distance between them
• gravity explains the motion between large objects very well
• Large objects are considered things that are larger than the microscopic scale
– so we are large objects, insects, dust and the sun are as well
![Page 9: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/9.jpg)
It is tricky though
• We really don’t know why or how gravity works
• We know how much gravitational force an object has
• we can predict its effect on another object
• we just don’t really know how it is generated or where it comes from
• But make no mistake, as it stands today, gravity IS NOT electromagnetic
![Page 10: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/10.jpg)
Gravity at work
![Page 11: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/11.jpg)
Strong Nuclear Force
• Lets talk atoms first• Atoms are composed of smaller subatomic particles called…
• Correct, protons, neutrons and electrons
• They usually contain the same number of electrons as they do protons
![Page 12: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/12.jpg)
neutrons
• Neutrons are neutral, this means they have no electric charge
• But, neutrons do have mass• Protons and neutrons are packed together tightly in the atom’s…
• Correct, the nucleus• See…
![Page 13: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/13.jpg)
![Page 14: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/14.jpg)
The strong force weakens…
• …as the particles get farther apart• Soooooo……..huh?• Its like this• When protons are close together, they are attracted to each other.
• This short-range force of attraction is much stronger than the long-range force of repulsion
• So if they are far away from each other they will repel
![Page 15: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/15.jpg)
SOMETHING LIKE THIS
STRONG FORCE
ELECTRIC FORCE
TOTAL FORCE
NO STRONG FORCE
ELECTRIC FORCE
TOTAL FORCE
![Page 16: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/16.jpg)
SIZE MATTERS
• Atoms with small nuclei, such as hydrogen, are held together more tightly because the particles are close together
• This allows for the strong force to act on most if not all the particles
• If a nucleus is larger, such as in uranium, the strong force between particles can only act on other particles that are close to it
• It won’t act on those that are far away• But, the repulsive, electric force acts on all of them
![Page 17: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/17.jpg)
• In many nuclei, the strong force is able to permanently keep the nucleus together
• These nuclei are stable• However if the strong force is not enough to hold the nucleus together, the nucleus decays
• This means it gives off matter and energy
• This “nuclear decay” is called radioactivity
![Page 18: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/18.jpg)
LARGE NUCLEI WILL DECAY
• Large nuclei tend to be unstable• In fact all nuclei that contain more than 83 protons are radioactive
• Awesomely enough, many smaller ones are radioactive also
• Even some with only one or a few protons
• Thanks universe!
![Page 19: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/19.jpg)
FUN FACT!
• Almost all elements with more than 92 protons DO NOT exist naturally on Earth.
• They have been produced in a lab
• They are so unstable that they decay almost immediately after they are made
![Page 20: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/20.jpg)
That’s the most fun fact ever!
SCIENCE IS AWESOME!
![Page 21: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/21.jpg)
Remember this?
STRONG FORCE
ELECTRIC FORCE
TOTAL FORCE
NO STRONG FORCE
ELECTRIC FORCE
TOTAL FORCE
![Page 22: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/22.jpg)
The weak nuclear force
• Is the one responsible for the decay
• If the protons get too far away from each other the weak nuclear force pushes them apart and the atom decays
![Page 23: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/23.jpg)
Let’s Talk Energy
• What is it?
• There are several definitions.
• This one is found in several textbooks:
• “The ability to do work”
• Okay, but what is the definition of work?
• If you don’t know, then this definition is useless
![Page 24: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/24.jpg)
Here’s one that is better but pretty vague
• “Anything in the universe that is NOT matter.”
• Okay so this gives you half of infinity, not very helpful
![Page 25: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/25.jpg)
Here is a good one...I mean it this time...well almost.
• But, to first understand energy we must understand matter. They go hand-in-hand ya’know.
• In fact, by Einstein’s definition, they’re the same thing E = mc2
• energy = mass times the speed of light squared• Plus, we find in nuclear reactions that matter and
energy are converted into each other...so they’re the same...I guess.
• But I digress
![Page 26: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/26.jpg)
Matter
• Sometimes defined as “anything with mass that takes up space”
• Okay..but what is mass?• Mass is defined as “How much matter is in something”• So by this definition, matter is “anything that is matter
and takes up space”
• not very good. It is also defined as anything that is NOT energy. Or, the other half of infinity. Again, not very good.
![Page 27: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/27.jpg)
Matter and energy
• These are the good definitions
• really
• for real this time
• really
• Matter: anything that can be detected with one or all of the five senses
• Energy: causes the movement and change of matter. CANNOT be detected with the five senses.
![Page 28: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/28.jpg)
Energy comes in many forms...
• ...well kind of
• its actually all just...energy but since it does so many things and effects matter in many different ways it is easy to think of it as different types
• What are some of them?
![Page 29: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/29.jpg)
Energy forms
• Light
• heat
• kinetic (1/2mv2)
• sound
• potential
![Page 30: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/30.jpg)
Lets talk about potential energy
• It alone comes in many forms
• chemical potential– stored in the chemical bonds of molecules
• gravitational potential– energy stored due to an object’s position above
the surface of Earth (GPE = mgh)
• electric potential– energy of a stored electric charge
![Page 31: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/31.jpg)
Law of Conservation of Energy
• Energy cannot be created or destroyed
• The amount of energy is constant in the universe
• it can change “forms” very easily but the amount never changes
![Page 32: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/32.jpg)
So this......is this
...is this
...is this
...is this
...is this ...is this.
![Page 33: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/33.jpg)
The Force/Energy Connection
• When a force is applied from one object to another, energy is transferred and converted from one form to another.
• All of the energy you use in a day came from the sun...ALL OF IT.
• How can that be true?
• Easy it just simply gets converted from solar energy to all the other forms
![Page 34: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/34.jpg)
Energy back into the universe as light, heat, sound, chemical potential
Nuclear fusion reaction
photosynthesis
Cellular respiration
Force applied to log
![Page 35: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/35.jpg)
![Page 36: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/36.jpg)
Work
• The scientific definition of work is different than the everyday definition
• W = F x d
• or…work = force x distance
• This means that to actually do work one has to apply a force to something and move it in the direction of the force
![Page 37: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/37.jpg)
Applying a force but NOT doing any work
Doing work
![Page 38: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/38.jpg)
The force/energy/work connection
• Let’s tie it all together
• To move something, one must apply a force to it
• In doing so, energy is transferred from one object to another
• If the object moves, work was done on that object
• But it is possible to apply a force to something but NOT do work on it
![Page 39: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/39.jpg)
Fun with math
• If you apply a 100 Newton force to a box, and you move the box 22 meters, how much work was done on the box?
• 2200
• 2200 what?
• The unit for work is the same as it is for energy
• so…2200 Joules or 2200 J
![Page 40: Physics: It Explains Everything. What is physics? Physics is the study of matter and energy It deals with how the two interact and interact with each](https://reader035.vdocuments.site/reader035/viewer/2022062802/56649ee45503460f94bf39fe/html5/thumbnails/40.jpg)
More About Force
• Of course the amount of force needed is directly proportional to the mass of the object
• What is a direct proportion?
• It means as the mass of the object increases the amount of force necessary to move it increases