# Tagged Questions

The velocity an object must travel to successfully exit the gravitational influence of a body.

9k views

### Does a gun exert enough gravity on the bullet it fired to stop it?

My question is set in the following situation: You have a completely empty universe without boundaries. In this universe is a single gun which holds one bullet. The gun fires the bullet and the ...
3k views

### When will the Moon reach escape velocity?

From what I know, the Moon is accelerating away from the Earth. Do we know when it will reach escape velocity? How do we calculate this?
3k views

### Why is there an escape velocity?

I've been trying for days, but I just can't understand why escape velocities exist. I've searched the web and even this site, and although I've read many explanations, I haven't been able to truly ...
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### How does escape velocity relate to energy and speed?

I have several confusions regarding escape velocity. I am sure I am missing something(s) obvious or maybe I am taught wrong. Lets say we throw an object of any mass at exactly escape velocity of ...
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### How long must escape velocity be maintained?

Escape velocity from Earth's surface is 11.2 Kilometres/second. How long would one need to maintain this escape velocity to actually escape Earth's gravitational pull? Must this 11.2 km/s velocity ...
2k views

### Escape velocity from long ladder

The escape velocity of earth is roughly $11 kms^{-1}$. However, what if a long ladder was built extending out of Earth's atmosphere and considerably more. Then if something was to climb up at much ...
398 views

### A vertical variation of modern versions of Michelson-Morley

For almost a year now, I have been in the uncomfortable position of having an idea. However, there is one nice thing about this idea. It makes a concrete, exact and relatively easy to test physical ...
12k views

### What is the escape velocity of a Black Hole?

The escape velocity of Earth is $v=\sqrt{\frac {2GM}{R}}$, where $M$ is the mass of the Earth and $R$ it's radius (approximating it as a sphere), and is much less than light speed $c$. But I want to ...
2k views

### Escape velocity to leave the water planet in the movie Interstellar

I saw this question and this question on the site a few days ago. It asks about escape velocity from the water-based planet in Interstellar and whether the black hole had any effect. Now, one question ...
1k views

### Movie Interstellar - Question about Escape Velocity

The movie Interstellar shows people on a water planet where time is dilated so much that 1 hour is equal to 7 years back on Earth. Even though they lift off from Earth using a Saturn-V two stage ...
5k views

### Can we escape Earth's gravity slowly?

I had a recent conversation with my girlfriend, who is a physics grad student. She was kind enough to listen to me rant about an idea concerning escape velocity. Unfortunately, I am still thinking ...
7k views

### When did Voyager-1 achieve Solar System escape velocity?

Wikipedia's page on escape velocity puts the escape velocity for an object travelling out of the Solar System at ~525km/s. This figure is slightly higher than the tentative velocity of Voyager-1 at ~...
694 views

### Rocket launch from a mountain

If we were to build a high speed rail up the side of a mountain like in some Science Fiction movies, what is the velocity needed at the point of leaving the mountain excluding angular momentum from ...
163 views

### Photon Escape Angle From Black Hole

Consider a photon source emitting photons near the surface of a Schwarzschild black hole. What angle, as a function of the source's radius from the event horizon, must the photons be emitted at such ...
100 views

### Escape velocity for Schwarzschild metric

I can't fill in the gaps in my solution to this and assistance or a reference would be appreciated. The question begins with the straightforward derivation of the EoM for a massive particle orbiting ...
3k views

### Could we make a trebuchet that could launch objects to a stable orbit?

Inspired by this xkcd, which calculated the energy requirements for accelerating individual humans to escape velocity (regardless of consideration for what that would do to your organs), I am ...
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### Escape velocity of satellites

I know that the equation for it is $$v^2 = \frac{2GM}{r},$$ and with that, the rocket should be launched at that speed. But could it go much slower spending much more fuel to escape from gravity right?...
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### Definition of event horizon - Gravity around blackholes [closed]

Put simpler: A black hole is surrounded by a 'sphere' where, to an outside observer. the speed of light is (near) zero. What is the radius of that 'sphere' (for a non-rotating black hole) and how ...
132 views

### Does the escape velocity of a black hole exceed $c$ *before* a singularity is created?

As an offshoot of the question Can we have a black hole without a singularity? I'm curious if the point of no return at which the massive object is condemned to become a singularity happens before its ...
688 views

### Finite velocity at infinite distance

If an object were launched exactly at escape velocity it would have zero velocity at infinity. But what if we launch an identical objects at greater than escape velocity? Apparently it will have a ...
255 views

### How far could the LHC “fire” a proton into space if we (outside LHC) ignore all interactions but gravity?

Very simple question, and frankly quite a silly one, but I'm currently writing a lecture for secondary school kids and I'd love to tell them how far the Large Hadron Collider could fire a proton. The ...
645 views

### How long will it take for a bullet to reach a Geostationary orbit?

I'm curious to know this. Neglect air friction and imagine a bullet that were shot normal to the Earth's surface, from the Equator. I will have to consider the Coriolis effect and so I expect the path ...
68 views

### How can escape velocity be independent of the direction of projection of a body?

I read that the escape velocity of a body is independent of the direction of projection. For example, I could throw a ball at $11.2$ km/s velocity horizontally, and it would still leave earth. I am ...
30 views

### Does light escape from highly dense bodies [duplicate]

If it were possible to launch a projectile at the speed of light from a body with the mass equal to that of our sun but a density such that its escape velocity was the speed of light how far would it ...
760 views

### While finding escape velocity, does human mass counts as the mass of Earth?

Escape velocity depends upon the mass of earth. my doubt is whether human mass adds into it or not? If it add then Earth's escape velocity would be increasing!
848 views

### Is escape velocity the same for all objects?

Would a lighter-than-air craft in the mid atmosphere at 80,000 feet altitude need to achieve the same velocity to escape earth gravity as the space shuttle?