1. ### B Escape Velocity depends on the Radius of the Earth?

We have 2 different formulas for escape velocity. and . If we look at the first formula we see that escape velocity is inversely proportional to the square root of Radius of Earth. While in the second formula, escape velocity is directly proportional to the square root of Radius of Earth. We...
2. ### Escape velocity of an iron asteroid

Homework Statement: Jack can jump upwards a distance 1.4 meters when he is on the surface of the Earth. What is his initial velocity when he jumps? Most of the time, however, Jack is in space. He is an asteroid miner: he looks for asteroids made out of useful metals. His job involves landing on...
3. ### B Question About the Escape Velocity from Different Mass Planets

Hi! I have a question about escape velocity. If a planet is bigger and have a greater escape velocity than another planet. Do this effect the density of the bigger planet in any way? Or do we have to know the mass of the bigger planet to know if the density is larger or lower for this planet?
4. ### I Escape velocity - General relativity

Hi, Do we obtain the same escape velocity equation: Ve = sqrt(2GM/r) using both Newtonian and Relativistic approach?
5. ### I Escape Velocity Confusion

Hey there, If body 1, mass M1 has escape velocity V_e1 = (2GM1/r)**.5 but M2 is more massive than M1 is this relation still valid? In this case, the subordinate body really isn't the subordinate body so does this still hold? And r (distance b/t the two) changes not only due to the motion of M2...
6. ### Find the speed of a satellite at a distance R from Earth

Homework Statement Gravitational force exerted on mass m is GMm/r^2 2. Relevant equations Orbital velocity at distance R from earth = ##\sqrt gR## Escape velocity = ##\sqrt 2gR## gR = GM/R Fc = mV^2/R F =m.a The Attempt at a Solution 1) express acceleration of gravity in terms of G, M , and...
7. ### I How does the speed of light affect expansion acceleration?

I may have a fundamental misunderstanding of the concept, but I was wondering, how does the accelerating expansion of the universe calculate for the time dilation in light travel? From my understanding, we know that the universe expansion is accelerating because the farthest galaxies that we...
8. ### B Escape velocity and kinetic energy of the Earth

If you had two masses, m_{1} and m_{2}, and you released them in space infinitely far apart, their kinetic energies would satisfy \frac{1}{2}m_{1}v_{1}^2+\frac{1}{2}m_{2}v_{2}^2=\frac{Gm_{1}m_{2}}{r} if they met with a distance r between their centres of mass. This equation therefore tells you...
9. ### I Forces and escape gravity

If I drive a plane and the force of engine is bigger than force of gravity of it , if the engine is turn on always ,and assuming no air , will the plane continue moving up and escape from the gravity ?
10. ### B An exercise related to the mass of the Milky Way, sort of.

So, in preparation to the Portuguese Astronomy Olympiads, I've stumbled upon this problem (exercise): The sun, which is 8 kpc away from the centre of the Milky Way, has a rotation speed of approximately 220 kms-1 . Whereas a a star that is 15 kpc from the centre of the Galaxy orbits at a speed...
11. ### Need help finding energy for escape velocity

Homework Statement The gravitational potential energy of a certain rocket at the surface of the Earth is -1.9x10^12 J. The gravitational potential energy of the same rocket 300km above the Earth's surface is -1.8x10^12 J. Assume the mass of the rocket is constant for this problem. A) How much...
12. ### I Trip to Space -- Can ship with 1g acceleration escape Earth?

In another forum, the question was raised, "could a ship with 1G acceleration escape the gravity well of a planet with 1G gravity?" A popular response is, if the craft is aerodynamic, it could accelerate laterally until it reached escape velocity and then manage to get to space. I don't...
13. ### B Need help calculating acceleration out of a gravity well

Hey, orbital mechanics! I can't find what I need to figure this out on the internet, and I don't do calculus so I don't understand all that I find. Help me make my next sci-fi novel plausible? I just did an Oberth maneuver around Sol, 21 radii (.0977 AU, 14,616,000 km) from center...
14. ### B How come escape velocity isn't imaginary?

Going through several definitions, it appears that escape velocity is equal to the potential energy. That is:$$\frac{1}{2}m v^2=-\frac{G M m}{r}$$but if I solve for velocity, $v$, I get:$$v=\sqrt{-2\frac{G M}{r}}$$So how do I get an escape velocity that isn't imaginary?
15. ### Relativistic escape velocity

Homework Statement Calculate the escape velocity on the surface of the neutron star in the previous problem (##m = \frac{2}{3} \cdot 2,1 \cdot M_{\odot}##; ##R = 15km##). Hint: Basic physics. Note, however, that the escape velocity is not going to be small when compared to the speed of light...
16. ### B What does a black hole look like from the inside?

According to this video, , if a black hole is large enough you could actually travel for some time within the event horizon without dying because the event horizon is so far from the actual singularity. So, assuming that's true, what would you see while you were inside the black hole? Here's...
17. ### Escape Velocity

Why does a planet's kinetic energy become 0 when it reaches infinity? And why does a planet's kinetic energy get converted to gravitational potential energy when subjected under another planet's gravitational field? Escape velocity seems very abstract to me!
18. ### Angular Acceleration and Moment Arm

Homework Statement [A rocket has landed on Planet X, which has half the radius of Earth. An astronaut onboard the rocket weighs twice as much on Planet X as on Earth. If the escape velocity for the rocket taking off from Earth is v , then its escape velocity on Planet X is a) 2 v b) (√2)v c) v...
19. ### I Escape velocity and kinetic energy

is it right to say, "when all the potential energy is converted in kinetic energy the object is moving at the escapevelocity. and "when the change in potential energy and kinetic energy is constant at the same time it is laying still on the ground or in a perfect circulair orbit. and the last...
20. ### I Escape Velocity = Freefall from Height of One Radius?

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 on each of these bodies, assuming the acceleration due to gravity remained constant during the fall...
21. ### Escape Velocity

If we provide a satellite with escape velocity perpendicular to the earth(radially), would it start orbiting it?
22. ### Why is black hole photon sphere outside the event horizon?

Homework Statement I am preparing a report on black holes and I recently learned about a phenomenon I was previously unaware of: the photon sphere of a black hole. While reading an article on said occurrence (I have now confirmed this on multiple sources) the photon sphere which is the minimum...
23. ### Escape velocity

If an object is thrown upwards with escape velocity, will it orbit the earth?
24. ### Escape velocity problem

1. Problem A rocket has landed on Planet X, which has half the radius of Earth. An astronaut onboard the rocket weighs twice as much on Planet X as on Earth. If the escape velocity for the rocket taking off from Earth is v , then its escape velocity on Planet X is a) 2 v b) (√2)v c) v d) v/2 e)...
25. ### Escape velocity earth confusion

Namaste If escape velocity on earth is 11 km/s and velocity of earth is 30 km/s how is that the atmosphere doesn't escape the pull of earth. Is the escape velocity with reference to earth ? I don't think so because when finding the formula we add kinetic and potential energy and then equate to...
26. ### Escape velocity for Saturn (Introductory Mechanics)

Homework Statement The radius of Saturn (from the center to just above the atmosphere) is 60,300 km (60300✕10^3 m), and its mass is 570✕10^24 kg. An object is launched straight up from just above the atmosphere of Saturn. (a) What initial speed is needed so that when the object is far from...
27. ### Escape velocity (from the earth) of the Earth-Sun system

Escape velocity is an estimate of the launch velocity of a spacecraft (without any propulsion) to overcome a planet system's gravitational pull in order to escape to infinity''. In this problem we consider both the gravitational attraction of the Earth and Sun (but ignoring the effects of...
28. ### Question about Space shuttle escaping Earth

My understanding is that for space shuttle to escape earth it needs to travel at a certain high velocity. So, what happens to the space shuttle if it doesn't reach the escape velocity at edge of earths atmosphere to space? The question i'm asking and the answer i'm seeking is something like...