Derivation of orbital velocity formula

In summary, the conversation discusses the derivation of orbital velocity based on altitude and acceleration without using calculus. The speakers mention using equations of motion, laws of gravitational potential and kinetic energy, and the relationship between centripetal force and gravitational force. They also mention the assumption of a circular orbit and the use of algebra and geometry in understanding the concept of acceleration and velocity.
  • #1
Amr Elsayed
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3
Is there some mathematical derivation for calculating the orbital velocity based on altitude and acceleration without using calculus? I thought of equations of motion, but I always get problems.
Is there a way to derive it using laws of gravitational potential and kinetic energy ?

Are the pieces of information here in the video correct ? I guess it has mistaken with the position of the satellite if not affected with gravity.
 
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  • #2
If you assume the orbit is a circle, you can do it without Calculus.

Set the force you need (for centripetal acceleration) equal to the force you have (Newton's law of gravitation).

The orbital radius is the Earth's radius plus the altitude.

Simplify.
 
  • #3
Dr. Courtney said:
et the force you need (for centripetal acceleration) equal to the force you have (Newton's law of gravitation).
But I need to use : F centripetal = M*V^2 / r .. Which needs calculus to be derived. I want to understand it without calculus if possible
 
  • #4
Amr Elsayed said:
But I need to use : F centripetal = M*V^2 / r .. Which needs calculus to be derived.

That isn't true. There are a few ways to show that ##a_{centripetal}=\frac{V^2}{R}## without calculus.
 
  • #6
  • #7
negligible mass satellite assumed
for stable orbit: gravitational acceleration = centripetal acceleration
so:
( G * M ) / r^2 = v^2 / r
 
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  • #8
You actually just need very little calculus, but you can instead think of it as the limit approaching to zero rather than the derivative and that should help you.
 
  • #9
Actually even the notion of instantaneous speed is based on calculus. So if you use instantaneous speed in the formula for acceleration you "use calculus".
Defining it as a limit rather than a derivative is still calculus. The notion of limit is one of the basic notions in calculus. And the derivative itself is such a limit.

So technically, you cannot do kinematics at all without calculus. You may have the illusion that you do without. :)
After all, Newton had to invent it before he can study motion.
 
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  • #10
A handy bit of info:
In a stable orbit two body situation, each body has equal momentum.
Have a look at this two body data sheet also.
 

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  • #11
Amr Elsayed said:
Can you please show me any of them using basic algebra or geometry ?

Even if you want to use geometry, you will have to use it in a way that allows for calculus (i.e. allow for derivatives) ...otherwise words like "Acceleration" or "velocity" won't make any sense...
As for basic algebra, I don't know what that would mean... like addition, multiplication etc?
 

Related to Derivation of orbital velocity formula

1. How is the orbital velocity formula derived?

The orbital velocity formula is derived using principles of classical mechanics and Newton's law of universal gravitation. It involves calculating the balance between the gravitational force of the central body and the centripetal force acting on the orbiting object.

2. What is the significance of the orbital velocity formula?

The orbital velocity formula is significant as it allows us to calculate the minimum velocity required for an object to maintain a stable orbit around a central body. It also helps us understand the relationship between an object's mass, distance from the central body, and its orbital velocity.

3. Can the orbital velocity formula be applied to any celestial object?

Yes, the orbital velocity formula can be applied to any celestial object as long as it is orbiting another larger object under the influence of gravity. This includes planets, moons, satellites, and even man-made objects such as spacecraft.

4. Is the orbital velocity formula affected by the shape or size of the orbit?

Yes, the orbital velocity formula takes into account the shape and size of the orbit. The velocity required for a circular orbit will be different from that of an elliptical orbit. The size of the orbit also affects the orbital velocity, with larger orbits requiring lower velocities.

5. What factors can affect an object's orbital velocity?

An object's mass, distance from the central body, and the mass of the central body are the main factors that can affect its orbital velocity. Other factors such as atmospheric drag, gravitational pull from other objects, and changes in the orbit's shape can also have an impact on the orbital velocity.

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