Newton's Big G and Earth's Little g

[@OutstandingOtter]

Respect for this guy. He was writing backwards that whole time just so the class could see everything as it was happening. Great teacher!

[@gradecracker]

Incredible that you’re writing backwards

[@FandangoJepZ]

I hope you’re joking

[@steffenleo5997]

Well explaines Prof Anderson... 👍👍

[@ednorton3026]

Excellent presentation. I teach chemistry at the local college & you are quite clear & easy to follow & understand.

[@rimmekohli8529]

Mr. Matt you are really a good professor...👍👍thanks for giving us some knowledge...to understand. Thank you

[@Venky_sir]

Hello Professor,I found this channel accidentally.I pray to god to have 1M subscribers for this channel..Unique way of teaching I liked it. My doubt is But,We use -g only for the objects which are verctically projected upwards... And I have one doubt F=mg From above equation g=F/m Which means mass is inversely propotional to gravity. But earth has more gravity than moon. From #India❤

[@carultch]

Lowercase g has the units Newtons/kilogram. It is a "coincidence" that this unit is identical to the units of acceleration, and in free fall, this is the acceleration of the object in question. I put "coincidence" in quotes, because there is a deeper reason as to why this is the case, but that's a topic for another day. The meaning of lowercase g is the gravitational force per unit mass of the object, that is in a gravitational field. It is a field strength, which means it is a force per unit property of matter of the object in the force field. Just as electric field is force per unit charge. g=F/m does not mean gravitational field is inversely proportional to mass, because F and m are both proportional to each other. It is gravitational field (and gravitational acceleration in free fall) that is the constant value, rather than the force. Gravitational field depends on the arrangement of the surrounding masses (both mass and proximity), but not on the mass experiencing the gravitational field.

[@manuboker1]

BEST PHYSICS LECTURES EVER !!!

[@tianhanipah9783]

Your lectures are very helpful, Sir!

[@TeacherNorainikhal]

I love your teaching sir

[@ravikataria1355]

you are a good sir

[@yoprofmatt]

Thank you. Glad to hear it. Cheers, Dr. A

[@alishakhan-ss5cf]

you are simply awesome

[@yoprofmatt]

Thanks for the feedback. I'm working on more. Cheers, Dr. A

[@michaelschuler7397]

Are you really writing backwards ?

[@craftypika6028]

Cheers Dr. A✌✌

[@yoprofmatt]

Crafty Pikachu, And cheers back to you! You might also like my new website: www.universityphysics.education Cheers, Dr. A

[@hasanmondol6422]

I understood perfectly and I'll try to do some example

[@yoprofmatt]

Excellent. Cheers, Dr. A

[@timschmidt-morsbach7671]

Thank you 🙏 for the video

[@yoprofmatt]

You are welcome. Cheers, Dr. A

[@sarahalfareh8400]

Man I wish this guy was my professor

[@yoprofmatt]

Glad to at least be here virtually for you. Cheers, Dr. A

[@pabloalfonso481]

Hi Professor. I have a question: I calculated the Fg between Jupiter-Sun for example and then Earth-Sun and my result was Fg J-S bigger than E-S. Is ok? If that is the case, Why Jupiter isn't orbiting more nearer to the sun than our planet?. Sorry, I don't understand. Thanks!

[@yoprofmatt]

The mass of the planet drops out. When a body is in a circular orbit (earth and jupiter are in nearly circular orbits), the gravitational force Fg=Gm1m2/r^2 is responsible for keeping it moving in a circle, which we call the centripetal force and equals Fc=m2v^2/r. Set them equal and use v=2πr/T and you can solve for Kepler's Law. See this: kzbin.info/www/bejne/fnuUl3uGr82ekK8 Cheers, Dr. A

[@pabloalfonso481]

@@yoprofmatt Thanks professor for the answer! I saw that video and use Kepler's Law. Now the results have more sense!

[@Highonfmusic]

How do u write d other way round?

[@VndNvwYvvSvv]

He doesn't. He's writing normally right handed and a camera in the other side of the glass recorded it backwards. Then they flip the video when it's recorded.

[@nawadipkandel3973]

but then there are students on other side of the glass. If he writes normally, it will be backwards for them.

[@carultch]

@@nawadipkandel3973 The students who see him in person, see a live video feed of the video he is recording on an adjacent big screen monitor. They can see both the reversed writing through the glass, and the mirrored correction he does to rectify it. He has to clarify to his live audience to watch the video, rather than their direct view of him, when he does demonstrations of the right hand rule, since he deliberately switches to his left hand, so that the image of him in the video appears to be using his right hand.

[@sanketpatil8557]

nice

[@philvinet4145]

nice video...however he did not follow the formula correctly....How many people can spot the flaw?

[@yoprofmatt]

Thanks for chiming in. At what time point did I blow it? Cheers, Dr. A

[@sujathabaskar8907]

I wish u were my physics teacher

[@daspecialist1220]

Am i the only one who saw he didnt speak to little g compared to big G?

[@jeffheath2314]

@what point does gravity begin and cyntrfical force begin!?

[@yoprofmatt]

Don't know what cyntrfical force is. Do you mean centripetal force? That only comes in to play when we start talking about rotation. In this example, we're assuming a non-rotating earth. Cheers, Dr. A

[@jeffheath2314]

Matt Anderson i mean lets say earth started as a meteor it then gets pulled in to a galactic gravity and begins to spin at that point in the begining of its spin wouldn't things on the surface fly off !? At what point would gravity begin i hope this is a clearer question!?

[@yoprofmatt]

Okay, here's an example. Let's say we're going to start spinning the earth faster and faster until objects start to fly off. The break-even point is when the force of gravity "mg" is just equal to the centripetal force "mv^2/R". Setting those equal, we can solve for "v=sqrt(gR)". If you plug in numbers for the earth (g=9.8m/s^2 and R=6.4x10^6m) you get "v=7919 m/s" which equals 17,714 mph! Interesting factoid: this is pretty close to the speed of the International Space Station in its orbit, by the way. Since earth is rotating at about 1000mph, we are in no danger of flying off. (Note: for a different planet than earth, you will need a different value for g. Or just use Newton's universal gravitation: F=Gmm/r^2.) Cheers, Dr. A

[@jeffheath2314]

Matt Anderson thank you for responding excellent answer ! Now at what exact location and time would this exchange of fields would take place what else might take place in an event like this of this magnitude!?? What would the earth have looked like at this precise moment!? How long ago did it take place?

[@carultch]

@@jeffheath2314 If Earth were spinning fast enough for the centrifugal pseudoforce to completely nullify gravity, Earth would've never formed in the shape we know and love in our timeline. Planets form to a shape that is consistent with hydrostatic equilibrium, where the apparent gravity at its surface pointing perpendicular to its surface. With the exception of local topography, Earth is consistent with the geoid shape that would eliminate all lateral apparent forces of gravity and the centrifugal effect. The dwarf planet Haumea is an example of a world where the rotation dominates gravitation, rotating once in 4 hours. It formed to shape is that is so extreme, you can see the eccentricity of its shape in photos with your own eyes. With a photo of Earth, you have to carefully measure a photo to know it is not a perfect sphere, as a photo of Earth appears to be a perfect circle. But with a photo of Haumea, you immediately see the bulging. Suppose you were to force Haumea to solidify in a sphere instead of this shape, with the same mass and angular momentum. Haumea would spin so fast, that objects at its equator would fall upward. Haumea would depend on structural forces in its solid crust to maintain a hypothetical spherical shape. The stress would likely cause its materials to rupture, and it would spin apart. The material would collapse back to a shape that could satisfy hydrostatic equilibrium, which is the ellipsoid we see today.

[@dannykeane6191]

Ok but how does he write backwards

[@yoprofmatt]

He's not THAT cool: kzbin.info/www/bejne/eYirfqeJg7Crj6M Cheers, Dr. A

[@mukulbandewar1450]

1good child

[@mukulbandewar1450]

Child guy go udyog Dixit