### Categories

### RSS Feed

### Search NewtonExcelBach

### Archives

### Top Posts

- Commenting a block of code in VBA
- Using Goal Seek on Multiple Cells
- Solving Quadratic, Cubic, Quartic and higher order equations; examples
- Downloads by category
- Taming Symbols in Excel
- Weighted Least Squares Regression, using Excel, VBA, Alglib and Python
- Using LINEST for non-linear curve fitting
- Cubic Splines
- Retrieving unique values from a range or array ...
- Downloads

### Recent Comments

Lambda and VBA | New… on Two New Functions; Let and… dougaj4 on Eval and Let examples dougaj4 on Eval and Let examples TB on Eval and Let examples dougaj4 on Eval and Let examples pgalvan@sigmaingenie… on Eval and Let examples dougaj4 on Eval and Let examples Craig on Eval and Let examples Craig on Eval and Let examples dougaj4 on Downloads Eval and Let example… on Evaluating text – u… Eval and Let example… on Evaluating text with units and… Eval and Let example… on Two New Functions; Let and… rhochoa81gmailcom on Downloads Ebony Buckle, New Sc… on George Gently, Matty Groves, a…

# Category Archives: Differential Equations

## The hole through the middle of the Earth – revised transit time

In the previous post in this series I produced a table of acceleration due to gravity against depth from surface, based on the four layers of the Earth (Crust, Mantle, Outer Core, Inner Core), assuming a constant density for each layer. … Continue reading

Posted in Differential Equations, Excel, Newton, UDFs, VBA
Tagged Excel, hole through the middle of the earth, ODE Function, UDF, VBA
3 Comments

## The hole through the middle of the Earth – acceleration

In my first go at modelling a ball falling through a hole through the middle of the Earth I assumed constant density, and hence the acceleration at any point was proportional to the distance from the centre. That is of course … Continue reading

## Elegant solutions, Column buckling, and the hole through the middle of the Earth

The previous post presented some examples of solution of differential equations using an iterative process, including the simple harmonic motion problem of a ball falling through an evacuated hole through the middle of the Earth. The final example was concerned … Continue reading

Posted in Beam Bending, Differential Equations, Newton
Tagged column deflections, differential equations, Euler buckling
5 Comments

## Using the AlgLib ODE (Runge-Kutta) Solver with Excel

Or to be more correct, the AlgLib Cash-Karp Solver, Cash-Karp being a refinement of the Runge-Kutta method of solving ordinary differential equations. Solution of differential equations is an iterative process requiring the repeated application of the solver routine followed by evaluation of … Continue reading

Posted in AlgLib, Beam Bending, Differential Equations, Excel, Maths, Newton, UDFs, VBA
Tagged AlgLib, buckling, Cash-Karp, differential equations, Excel. VBA, hole through the middle of the earth, Runge-Kutta, SHM, UDF
8 Comments

## Elegant solutions, Simple Harmonic Motion, and the hole through the middle of the Earth

No, not the hole (beloved of conspiracy theorists everywhere) where our alien overlords keep their UFO’s, but rather the equally imaginary hole from Pole to Pole (beloved of physics teachers everywhere) where we can drop in objects and watch them travel … Continue reading