Physics in a manual angle grinder machine

[flyguille]

First, I am not a physician (just a normal guy from Argentina), and I know the short answer for the following question is "it isgyroscopic effect". But why?... My original question was:

"I feel the effect when using "motor angle grinder", when turn off, you can move it any direction easy, when turn on, it is hard to move any direction, it is like it crates a force that act against left-right-up-down movement, but, iirc moving far-near from my body (called it z axis movement) don't feel that force opposing. And I don't understand why this happen, name it gyroscopic force, but... how the it interacts with external movements applied to the whole body of the machine?..., so then I started to thinking, about crazy things gravity and mass... Is the fast movement of mass disturbing gravity and that is the "gyroscopic effect"? if so, why don't create our own gravitational environment...out of a big machine with that effect. Or I am just too ignorant that don't understand about gyroscopic effect apart from it maintain the motorcycle straight up!."

What is more amazing there is an opposing force moving the machine down!. So it will fall slower if turn on?.

Why is this opposing force against movement of the whole machine?

 

[tnich]

First, I am not a physician (just a normal guy from Argentina), and I know the short answer for the following question is "it isgyroscopic effect". But why?... My original question was:

"I feel the effect when using "motor angle grinder", when turn off, you can move it any direction easy, when turn on, it is hard to move any direction, it is like it crates a force that act against left-right-up-down movement, but, iirc moving far-near from my body (called it z axis movement) don't feel that force opposing. And I don't understand why this happen, name it gyroscopic force, but... how the it interacts with external movements applied to the whole body of the machine?..., so then I started to thinking, about crazy things gravity and mass... Is the fast movement of mass disturbing gravity and that is the "gyroscopic effect"? if so, why don't create our own gravitational environment...out of a big machine with that effect. Or I am just too ignorant that don't understand about gyroscopic effect apart from it maintain the motorcycle straight up!."

What is more amazing there is an opposing force moving the machine down!. So it will fall slower if turn on?.

Why is this opposing force against movement of the whole machine?

I suggest that you try another experiment. Turn the machine on, hold it steady in your hand, and walk in a straight line. Do you feel any resistance then (except from the chord when it pulls you up short)?
The gyroscopic effect should happen when you turn the machine, but not when you move it in a straight line without turning.

 

[flyguille]

ok, I will do a battery of tests, I remember it require more considerable force moving to facing the rotating grinder. So, if the rotating disk is horizontal, include I remember it require more force to move up or down, but maybe I am confuse, in a couple of hours I will do tests and posts results.

 

[tnich]

ok, I will do a battery of tests, I remember it require more considerable force moving to facing the rotating grinder. So, if the rotating disk is horizontal, include I remember it require more force to move up or down, but maybe I am confuse, in a couple of hours I will do tests and posts results.

Let me rephrase something I said before, just to make sure we are understanding each other: The gyroscopic effect should happen when you rotate the machine, but not when you move it in a straight line without rotating it.

 

[flyguille]

yes, I understood that phrase.

 

[tnich]

. . . about gyroscopic effect apart from it maintain the motorcycle straight up!."

It does more than keep the motorcycle from falling over. Have you ever noticed how you steer when you ride a motorcycle or a bicycle? When you want to turn left, you don't grab the handle bars and turn the front wheel to the left. You would fall to the right if you did that. The way you turn left is to lean to the left. Then the front wheel turns toward the left, even if you are not touching the handle bars.

 

[Dale]

So it will fall slower if turn on?.

It will not fall slower when it is turned on. You could test that by turning it on and dropping it and turning it off and dropping it and comparing the time. Although if it were my grinder I would not want to do the test.

 

[sophiecentaur]

It does more than keep the motorcycle from falling over.

Be careful to read this carefully. The resulting torque is not enough to resist falling. You would need an enormous flywheel to do that. The torque steers the wheel as the bike tilts and the direction of steer (luckily?) steers you into the curve and brings the bike upright.

 

[flyguille]

ok, yes, the vibration of the grinder machine make it confusing to feel.

Looks like it don't oppese to linear movement, but to rotating on several axis, I imagine one axis is the grinder element itself, other is the motor-gears inside, so it has opposing forces to rotating in several axis.

And it is amazing, I know that the gyroscopic effect is done by the mass has angular cinetic momentun going to the original direction. right?, so if its wheel-axis want to apply a force to change that direction, the mass of the rotating element will oppose to it.

I know what exactly it is and I feels amazed, how the mass has relative spatial knowledge of where it want to go.!

 

[sophiecentaur]

I know what exactly it is and I feels amazed, how the mass has relative spatial knowledge of where it want to go.!

I agree. It really does feel odd. There are many uTube videos available. Try this one Hopefully it can help with your understanding.

 

[A.T.]

I know what exactly it is and I feels amazed, how the mass has relative spatial knowledge of where it want to go.!

Here is a good video that explains it via linear dynamics: