Mersa wrote on Aug 28^th, 2017 at 12:09am:


What then do we know ??? That larrys stone would have had a spin that lifts his stone is speculated too.

But one is for sure: Energy for rotating the stone is a subtrahent to the energy for throwing a stone. Also a spinning stone is no "perpetuum mobile" for winning distance out of nothing.

Mersa wrote on Aug 28^th, 2017 at 1:51am:


I don't mean to lose this in an avalanche of posts. This is another layer of complication that could affect the result. It's an open problem as to how much or little the lift would effect the result. It could be nothing or it could be significant.

It's also a handy example of how not all mechanics is 'high school level'! 

JudoP wrote on Aug 28^th, 2017 at 5:51am:


And I explained, they are (and how and why they are ... to add)!

JudoP wrote on Aug 28^th, 2017 at 5:51am:


Correct! To see comparabilities, "parables", connections and / or together hangs is not one of your talents.



My tip to you: Remember the topic and imagine a pendulum or turntable (what is as big as the earth, the orbit of our moon or as big as your slinging circle) as I have recommended while posting my first drawing (Image P-01).

JudoP wrote on Aug 28^th, 2017 at 5:55am:


magnus effect is not in mechanics but in fluid dynamics(much more difficult)

no speculation on larrys stone spin. I've held it. It's more or less glande shaped. So you don't get sphere rotational lift.

As to the rest of the argument  - do either or you still know what you are arguing about ?

It does seem to have resorted to simple name calling - albeit couched in physics terminology

JudoP wrote on Aug 28^th, 2017 at 6:29am:


Aha!?? Please show or name us this post of mine (means: ... that post, where I wrote: "velocitys are without justification"). And then tell us the justified velocity of sun and / or earth (in a justified inertial-system or justified point of view)!

Or tell us instead of this, why only your point of view should be the "justified one": Turns the earth clockwise or counterclockwise ... watched from your point of viewing or "banking"?

Quote:


Ok- I'll just summarise everything, though I fear I'm just repeating myself:

I've already said the route to a correct answer is analyzing the forces involved in a free body diagram and calculating the resulting accelerations. That's just your standard application of Newtons laws- it's how you solve basically any mechanics problem, my justification in saying this is that Newtons laws are correct(!)- (this is the part that you look down on as the 'easy grammar school physics' yet you have not managed to apply such physics, and have made claims in contradiction with such physics! eg: velocity always in the same direction as the force)

Just adding angular and linear velocities is not how mechanics works. It's an assertion that is unsupported. Have you considered how moving your hand changes the force of tension you apply along the sling- that alone means you can expect the angular velocity to change as you move into the throw. (Justification- by Newtons laws circular motion is directly caused by the centripetal inwards force (tension on the string towards your hand)- change the force or the direction of the force and you change the acceleration and therefore the angular velocity of the projectile).

The earth, the sun whatever else don't come into it and frankly I have no idea what you mean with those questions. The above point is the only question of relevance and needs to be addressed: How do you justify just adding the velocities?

I think I've said all I can say on this without rehashing. I've put the information out there and any more would just be going in circles or repeating myself.

I'm not sure if you believe I have a degree or not (can prove if not) but *please* consider that someone who has studied this stuff for years at a level well above high school (and who has actually taught high school physics for a time!) might know a bit more about it than a keen amateur. As I said before, I'm not doubting your claims and long distance throws, only your theory of how it happens. In fact if anything, theories involving the increase in angular velocity probably make higher projectile speeds more rather than less believable.

Honestly, I hope this is not felt too adversarial for you, I can see how my words could be read as such, but this forum is a nice space and I genuinely bear no ill will. Though I do value directness and getting things correct a lot in this realm (of physics).

If you can describe more of your throwing strategy to achieve high range I'd happily defer in that realm and be a keen student as my max range is probably no further than 200 or so meters, if that.