Tag Archives: hole through the middle of the earth

Falling Faster

A recent paper by  Alexander Klotz of McGill University, Montreal, has stirred a bit of interest in the pop-science press.  The paper looks at the old question of the time taken to fall through a hole passing through the centre … Continue reading

Posted in Excel, Maths, Newton | Tagged , , | 4 Comments

The hole through the middle of the Earth – filled with air

Three air molecules go into a hole,  Well, I say three; could have been four or five.  Could have been nine or ten, doesn’t matter. Could have been fifteen, twenty – fifty. Round it up. Hundred. Let’s go mad, eh … Continue reading

Posted in AlgLib, Differential Equations, Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , , | 4 Comments

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 , , , , | 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

Posted in Differential Equations, Newton | Tagged , , , | 2 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 , , , , , , , , | 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

Posted in Differential Equations, Maths, Newton | Tagged , , , | 5 Comments