ESCAPE VELOCITY

[@jimslater3574]

A Quick and (Somewhat) Dirty Way to Calculate Escape Velocity I was doing some calculations using the escape velocities from Earth, Moon and Mars. Then by chance I calculated the velocities attained when an object was "dropped" from a height of the radius of each of these bodies, ASSUMING THE ACCELERATION DUE TO GRAVITY REMAINED CONSTANT DURING THE FALL. Escape velocity is the minimum velocity needed to escape a gravitational field. For example, escape velocity on earth, Vesc = 40,270 km/h (given). Using the simple formula V2 = (2ar)^0.5, where V2 = velocity after falling distance r; a = acceleration due to gravity; r = radius of earth (initial velocity = 0), and a = 9.80665 m/s^2 r = 6,378,000 m V2 = (2*9.80665*6378000)^0.5 = 11,184.53 m/s = 40,264.29 km/h This value of 40,264 km/h compares very closely to the escape velocity of 40,270 km/h I thought perhaps this was a coincidence, so I calculated V2 for the Moon and Mars and compared them to the known escape velocities for each body. Moon: Escape velocity = Vesc = 8,533.6 km/h a = 1.62 m/s^2 r = 1,737,150 m V2 = (2*1.62*1737150)^0.5 = 2,372.418 m/s = 8,540.7 km/h Again, a very close fit. Mars: Escape velocity = Vesc = 18,108 km/h a = 3.72761 m/s^2 r = 3,389,500 m V2 = (2*3.72761*3389500)^0.5 = 5026.875 m/s = 18,097 km/h Another very close approximation. I haven't done the calculations for the other planets, moons, or the sun, but I expect I would get similar results. From these results I speculate that Vesc = V2. This seems to be a quick and dirty formula for calculating escape velocity, and might be handy for a stranded astronaut. But am I really just reiterating Vesc = (2Gm/r)^0.5? (G = gravitational constant; m = mass, e.g., of earth; r = radius, e.g., of earth). I any case, using this method avoids a lot of the very intricate calculations necessary for determining Vesc the standard way, as long as the acceleration due to gravity and radius are known. Sources: www.livescience.com/50312-how-long-to-fall-through-earth.html keisan.casio.com/exec/system/1360310353 www.wolframalpha.com/input/?i=escape+velocity+Mars

[@user-vl2ol1nk4x]

wow. you are a legend. you took so much time writing this comment, yet you got only two likes (likes have no value anyway), and i am the first one to reply.

[@user-vl2ol1nk4x]

i will try to mathematically prove, or disprove this. I will reply if i reach somewhere. Good job (●'◡'●)

[@scar6073]

Thanks you so much for making these videos. I really love how you explain things ❤️

[@MARTKARBLE]

@roland smith : While photons are directly affected by gravity since they dont have intrinsic mass. Their path in a straight line is warped by the surrounding fabric of the universe (spacetime) hence their paths they follow are straight but over a curved surface distorted by large masses due to gravity. I think...

[@anitb1874]

Mr. Mister I agree👍 I was thinking this too...

[@LLiimmzz]

thank you sooo much for these videos keep the good work up you really helped me alot :) thank you very much

[@tenbiteermias1480]

Are you still alive

[@pavanraghav3650]

@@tenbiteermias1480 lmao

[@craigfitzsimmons8412]

thanks for doing this! Much appreciated.

[@kryptynite76]

I hope my explanation didn't confuse you further. I apologize if it did.

[@divyadivya2991]

thank you so much for these videos ........😊😊😊

[@divyadivya2991]

why isn't squared🤔🤔

[@alienware5172]

V= √2* 9.81* (6.4*10^6) = 11.2 km/s earth escape velocity ... √2 * g is gravity of earth * radius of object in this case earth .

[@charbsbro3170]

why isnt it squared?

[@6iaZkMagW7EFs]

Re?

[@Taifune81]

This is involving energy. If the r was squared it would be referring to the gravitational force between two bodies. R on its own is potential energy

[@climatixseuche]

Why does a rocket need a certain escape velocity to escape earths gravity? Meaning why does the rocket need to reach a certain speed, would not be also possible with lower speed but a longer burn time?

[@lasseviren1]

The concept of escape velocity is not really for rockets that are burning fuel. A rocket moving upward at a constant speed of 1 m/s will eventually move to a location where the gravity from the earth was extremely small. So the concept really applies to an object that only uses its kinetic energy to escape the planet. No other energy from fuel or other sources. Almost like a rock that has just left a sling shot and is heading upward.

[@thecontroller6786]

Why is (-GMm/R) potential energy?

[@ganeshmurmu2826]

because potential energy is always against gravity so negative

[@oneinabillion654]

Because that's just how it is derived

[@M4cc4n4]

Well the Force is equal to the negative of du/dx or dr in this case Where U is the potential energy So you get the equation -GMm/R^2 = -du/dR Integrating both sides gives you -GMm/R = U which is what you asked

[@moo9950]

why does v=0 when approaching infinity , wouldnt the object go on and on and on until it hit something

[@k.c.s6249]

thanks bro.thats help full

[@mcdonrolando]

Einsteins light bending around the moon during an eclipse disproves "escape velocity." How can light, which is moving faster than the escape velocity of the moon respond to the moons gravity? Someone correct me! Where am i wrong?

[@6iaZkMagW7EFs]

Roland Smith I hope you are Joking.

[@6iaZkMagW7EFs]

Something can respond to gravity, but still escape. A if you shot a bullet straight up on Pluto, it would likely escape, but would be slowed by gravity, and its path warped if you shot it sideways.

[@apolloniuspergus9295]

You must be joking

[@apolloniuspergus9295]

Or you really don't understand what escape velocity is about

[@LaBonbonFraise]

Roland Smith cool Story bro

[@senseisparky2844]

Thank you!

[@chrisucc124]

I do not thing photons can be effected by gravity, correct me if i am wrong

[@6iaZkMagW7EFs]

chrisucc124 Newtonian physics is not perfect. The 'warping' or spacetime means that photons are effected by gravity, traveling is a curved straight line.

[@vincentnwosu7053]

photons are particles of light and have weight. Anything that has weight is affected by gravity.

[@NSS9749]

I was looking more for the: how did anyone got this V escape value of 11.2km/s approximately 25,000mph.

[@raychen4090]

nivea saman Did you try plugging the radius and mass of Earth into the equation? Thanks

[@amgee007]

The escape velocity is sqrt(2) times the answer in the 2nd problem, in the opposite direction of course. That's interesting. I'm doing this in my head on the phone, so I could be making a mistake.

[@animeDaisuki404]

Thought all have been multiplied with 2, why V^2 is still 1/2V^2

[@kryptynite76]

Well this is what Einstein craved to know the answer to, which he found in his theory of general relativity. In the most simple explanation, general relativity says than objects that have gravity bend or warp space-time and light moving through space has to follow the warped path. If you imagine space as a sheet of that is bent paper (space is actually 3D but this is an analogy) and were to pull it, the bends disappear and an object that moved in that bent path can now move in a straight one.

[@aungkyawkyaw4373]

why at infinity v=0?

[@lasseviren1]

Because if it had some speed at infinity that means you didn't send it out at the slowest speed from the planet in order to just barely make it to infinity.

[@adamfirst3772]

Aung Kyaw Kyaw because the WHOLE THING is IMAGINARY... and the values can be WHATEVER they want.... this absurdity is about how hard you need to throw a rock to go past the universe...

[@adammadrisotti6942]

@Adam First No, the values are not arbitrarily chosen. Rather, velocity at distance infinity needs to be zero to guarantee the object will NEVER return again. If the velocity of the object reached zero at any other distance than infinity, the gravitational pull of the planet would eventually drag it back to where it started. As escape velocity is the speed at which an object escapes a body’s gravitational sphere of influence for good, it must not return and therefore will not reach a velocity of zero at any distance below infinity.

[@therewasonceacatnamedmeimc247]

Why is the comment section brimming with oversmart nerds?!?

[@monkeysinthearctic971]

thanks mate

[@Ja06.]

i was born 11 days before this vid came out

[@totu7071]

Thank you so much Sir

[@Tri_Nguyen_]

lol, u crossed out the wrong mass near the end

[@therewasonceacatnamedmeimc247]

Lmfao . That is so funny i am rolling in laughter!! Lol! Lol! Hear hear!! 😶😑

[@kevinbonin6173]

Your math doesnt traspose to reality. Space can not exsist stated by the 2nd law of thermodynamics. A gas and a vacuum can not be next to each other.

[@alexwashburn9414]

banger

[@ts377]

thank you

[@sydneygersbach9799]

i would have died in my class if it wasnt for this

[@budeidei]

it is GMe/2R , he is correct. It's just that he cancelled the Me wrongly.Instead he should cancel the Mh. Overall, nothing wrong

[@feastures]

Rockets don't need to 'add speed'.

[@himadritripathi6035]

Thanks a lot sir..

[@aromelzeus6317]

ithil enghanayaaaaaa vettypovukaaaaaaaaaaaaaaaaaaaaaa

[@debajyotisaha5523]

Pronounce without casualness.explain slowly.