haruspex's latest activity

Ok, I'll give you that one.

No, that doesn’t work either. You cannot add angular velocities that are around different axes. What axis would the resulting angular...

Good. That's unlikely to work. Energy conservation equations are time independent . No, you can't do that. The motion of a rigid body...

Right

The arrows on the airflow show the relative motion. If the air is actually still, which way is the ball moving?

I have a feeling I have misled you on statement 1. From experience, there should be downward pressure on the ball. And if the air is...

Yes, and the reasoning you give is ok. I would have described it as the flow lines are compressed below so the air pressure is greater...

If ##x=y ## then ##x^2=y^2##. If ##10cm=(1/10)m## then what is ##(10cm)^2##?

Yes, you do seem to have a sign error in post #59, but where exactly it is depends which sense you are taking as positive for each...

If you mean compared with what I posted in post #60, I only meant that your numerator/denominator term reduced to that. I dropped the...

Factorise the denominator.

Which reduces to ##\frac {5g\sin(\theta)}{7(R-r)}##. Do you know what the answer is supposed to be?

Yes.

https://en.wikipedia.org/wiki/Moment_of_inertia disagrees. "The moment of inertia, otherwise known as the mass moment of inertia...

I would argue strongly against thinking of this "effective MoI" as really being an MoI. MoIs arise usually in three contexts: Angular...