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pnachtwey

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- TL;DR Summary
- From viewing golf and table tennis balls with back spin, you can see the balls float or even rise against the force of gravity. This means the force due the Magnus effect is relatively equal to that of gravity but in my simulation, the force due to the Magnus effect is much more. Why, What did I do wrong or are my calculations correct?

I have made a simulation of a table tennis ball being hit and landing on the table. There are 5 differential equations that are integrated to compute the horizontal position, horizontal velocity, vertical position, vertical speed and spin. by integrating 5 differential equations simultaneously I have checked the units so when I divide the forces due to gravity, viscous friction, damping and the Magnus effect by the mass of the table tennis ball, I get units of meters per second squared as expected.

What I didn't expect is that the acceleration, actually deceleration, due to drag and Magnus effect would be many times that of gravity. The calculations look correct but it bothers me that the Magnus effect should be so high.

Often a golfer will drive a ball and you can see it lift during the flight. In this case the upwards force due to the Magnus effect is a little greater than that caused by gravity. However, in my simulation the force due to the Magnus effect is 10 times that due to gravity. A table tennis ball "chopped" with heavy back spin will appear to rise a bit or float like a golf ball but it doesn't accelerate up as my simulation would suggest. This doesn't seem right.

I have attached my work. It shows all the calculations and at last two pages I do the units check to makes sure all the units are consistent.

Can anybody find what is wrong or right with my simulation? The trajectory looks good but I don't believe the high forces due to the Magnus effect.

What I didn't expect is that the acceleration, actually deceleration, due to drag and Magnus effect would be many times that of gravity. The calculations look correct but it bothers me that the Magnus effect should be so high.

Often a golfer will drive a ball and you can see it lift during the flight. In this case the upwards force due to the Magnus effect is a little greater than that caused by gravity. However, in my simulation the force due to the Magnus effect is 10 times that due to gravity. A table tennis ball "chopped" with heavy back spin will appear to rise a bit or float like a golf ball but it doesn't accelerate up as my simulation would suggest. This doesn't seem right.

I have attached my work. It shows all the calculations and at last two pages I do the units check to makes sure all the units are consistent.

Can anybody find what is wrong or right with my simulation? The trajectory looks good but I don't believe the high forces due to the Magnus effect.

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