Linked Questions

231
votes
11answers
53k views

Don't heavier objects actually fall faster because they exert their own gravity?

The common understanding is that, setting air resistance aside, all objects dropped to Earth fall at the same rate. This is often demonstrated through the thought experiment of cutting a large object ...
-1
votes
3answers
3k views

If an object fell from the moon [duplicate]

Ignoring the moons gravity, if an object sitting still (relative to the Earth, i.e. not in orbit) was dropped from the moon. How long would it take to hit the Earth?
2
votes
2answers
1k views

Basic question about law of gravitation [duplicate]

Possible Duplicate: Radial fall in a Newtonian gravitational field This is how Wikipedia defines Newton's law of Gravitation: Every point mass attracts every single other point mass by a force ...
0
votes
0answers
618 views

Gravity change as a function of time only [duplicate]

Is it possible to find how gravity changes with time? That is, height is not part of the equation. For example, $g$ can be expressed as a function of height that does not involve time with this ...
1
vote
1answer
148 views

Distance traveled in a simple two body problem [duplicate]

I'm trying to program an $N$-body simulation and I'd like to be able to test it with a known solution to a simple, two-body problem. I've looked at multiple sources, but I just don't know how to apply ...
1
vote
0answers
147 views

Position vs Time Function for a Falling Object Without Assumption of Constant Acceleration [duplicate]

If you have an asteroid for example and a planet, isolated from all other gravitational influence and initially at rest with respect to each other, how would you find a position vs time function for ...
1
vote
0answers
57 views

One dimensional motion with changing acceleration. Falling to a large body from a great distance [duplicate]

Possible Duplicate: Radial fall in a Newtonian gravitational field My math and physics are rusty. I am trying to calculate the time an object takes to fall to a large body. Before you answer $1/...
-1
votes
1answer
56 views

How do you calculate the displacement of an object moving with a changing acceleration? [duplicate]

Take an object a vertical distance $r$ above the surface of the earth of radius $R$. The acceleration due to gravity at any $r$ is therefore: $a=\frac{GM}{(R+r)^2}$ Lets say the object falls from ...
7
votes
1answer
2k views

Kepler problem in time: how do two gravitationally attracted particles move? [duplicate]

Two particles with initial positions and velocities $r_1,v_1$ and $r_2,v_2$ are interacting by the inverse square law (with G=1), so that $$ {d^2r_1\over dt^2} = - { m_2(r_1-r_2)\over |r_1-r_2|^3} $$ ...
0
votes
2answers
4k views

Time taken for object in space to fall to earth

The Problem For a small mass a distance $R_i$ away from the center of the Earth, how long would it take for the object to fall to the surface of the Earth, assuming that the only force acting upon the ...
3
votes
1answer
747 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 ...
-1
votes
1answer
268 views

Gravity: Velocity (and distance) as a function of time, but wait; there's more

First, ignore air resistance. Always ignore air resistance. Using kinematics for gravitational acceleration systems works within a specific scope, and when the system's scope widens too far, they ...
2
votes
1answer
146 views

Motion described by $a=\frac{k}{x^2}$

Say a particle in one dimension experiences acceleration inversely proportional to the square of displacement. What is its displacement as a function of time? $$ a=\frac{d^2x}{dt^2}=\frac{k}{x^2} \\ \...
0
votes
1answer
85 views

Solve the inverse function of the solution to a varying acceleration problem ODE

Suppose there are two positive charges $A$ and $B$, both with equal mass $m$ and the same charge quantity $q$. The initial distance between $AB$ is $R$; and the initial velocity of $B$ relatively to $...
0
votes
0answers
46 views

Two particles interacting by a inverse-square-law force, find their positions in function of time [duplicate]

Possible Duplicate: Two particles are interacting through gravitational forces. How to find their positions in function of time? Given the initial positions and velocities $r_1(0), r_2(0), v_1(0),...

15 30 50 per page