[jeffreyH (OP)]

J = 2GM/r^2sqrt(2GM[1/r-1/h])

[Bored chemist]

In what context?

[jeffreyH (OP)]

In what context?

Radial freefall.

[Colin2B]

J = 2GM/r^2sqrt(2GM[1/r-1/h])

Try r^3 instead of r^2

[jeffreyH (OP)]

J = 2GM/r^2sqrt(2GM[1/r-1/h])

Try r^3 instead of r^2

Obvious when someone points it out.  Thanks!

[PmbPhy]

J = 2GM/r^2sqrt(2GM[1/r-1/h])

You'll have to first explain to me what you mean by []gravitational jerk[/i]. Do you mean the jerk caused by the gravitational force? Jerk is defined as the time rate of change of the force on a body. In that expression you don't have the mass of the object which is being jerked.

Where did you get that expression from? You haven't described what you mean by this? Are you referring to the gravitational field of a spherical body having a spherical distribution of mass?

[jeffreyH (OP)]

J = 2GM/r^2sqrt(2GM[1/r-1/h])

You'll have to first explain to me what you mean by []gravitational jerk[/i]. Do you mean the jerk caused by the gravitational force? Jerk is defined as the time rate of change of the force on a body. In that expression you don't have the mass of the object which is being jerked.

Where did you get that expression from? You haven't described what you mean by this? Are you referring to the gravitational field of a spherical body having a spherical distribution of mass?

I doubt if it is the correct expression. I found it in my notes. Unfortunately I didn't make a mention of where it came from. Do you have any references I could use to find the right form for this?

[jeffreyH (OP)]

This appears,to be saner.
https://physics.stackexchange.com/questions/136880/is-it-possible-to-have-a-rate-of-change-of-acceleration

[Colin2B]

I doubt if it is the correct expression.

I assumed you had been differentiating the LH part GM/r^2 and then ended up with a typo when writing out.

[PmbPhy]

This appears,to be saner.
https://physics.stackexchange.com/questions/136880/is-it-possible-to-have-a-rate-of-change-of-acceleration

I see. That's the time rate of change of acceleration, not the jerk. To find the jerk on a particle in the gravitational field of a point source (or spherically symmetric body) you find dF/dt. So differentiate the expression F = GMm/r² keeping in mind that r is not constant. You should therefore have the term dr/dt in it. You have an "h" in your expression which you didn't define. You'll end up with J = -GMm(dr/dt)/r³

[jeffreyH (OP)]

I doubt if it is the correct expression.

I assumed you had been differentiating the LH part GM/r^2 and then ended up with a typo when writing out.

I found it in notes I had made a while back. It didn't look familiar but when you pointed out the r^3 it jogged my memory of something similar I had worked through. Some of my 'notes' are just pages of equations where I have left no cues as to what the hell I was doing.

For instance I have on a half torn out page (l^2/[2r^2])-m/r-ml^2/r^3. I have no idea what that was regarding!

[jeffreyH (OP)]

I am currently looking at this thread which seems of interest.
https://www.physicsforums.com/threads/finding-an-equation-to-represent-a-jerk.330872/