Derive equation of trajectory of a body around a fixed body attracted by gravity

AI Thread Summary
The discussion focuses on deriving the trajectory equation for a body of mass m orbiting a fixed mass M under gravitational attraction. The trajectory can be an ellipse, parabola, or hyperbola, depending on initial conditions like velocity and mass ratios. Participants mention using Newton's Law of Gravity and polar coordinates to solve the problem, noting that the calculations can be complex and lengthy. A request for resources on solving the Kepler problem is made, highlighting the need for guidance in navigating the intricate mathematics involved. The conversation emphasizes the relationship between initial conditions and the resulting orbital shape.
gupta.shantan
Messages
2
Reaction score
0

Homework Statement



There is a fixed spherical body of mass M whose center is to be taken as origin. Another body of mass m whose initial position vector \vec{r} is given. This body is projected with initial velocity \vec{v}. Find the equation of trajectory of body with mass m around the body with mass M.

Homework Equations



Will the trajectory be an ellipse, just like the orbit of Earth around the sun?

The Attempt at a Solution



I tried solving the position using Newton's Law of Gravity. I also tried using the formula a = v dv/dx and integrating but was unable to reach a solution.

Any help is greatly appreciated...
 
Physics news on Phys.org
Your problem is known as Kepler problem.

It is possible to derive the trajectory with Newton's Law of gravity, but this is an ugly calculation, at least ~2 pages long, involving polar coordinates, some substitutions and messy integrals.

Depending on the velocity, the radius and the masses M and m, the trajectory can be:
- an ellipse
- a parabola
- a hyperpola
which are all conic sections
 
thank you mfb
but i am willing to go through the messy mathematics. So can u please help me by giving me a link to where this Kepler problem has been solved.
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Back
Top