A bit of moonshine

A magnetised ball rolls around it with the compass's needle pointing to the ball at all times.

E4
Pretend you have nothing better to do right now and, thus, have to consider the Moon for a while - you know, the thing that at night gives us light and on which, many moons ago, American astronauts printed footprints? But here's the thing: we sentient beings on Earth get to see only one side of the Moon because only one side is visible to us since the Moon rotates about its spin axis at the same rate that it orbits the Earth, a situation known as synchronous rotation or tidal locking. Okay, so far so good, but there's this question: during one revolution around the Earth, has the Moon also rotated once around its axis? If you think about it, obviously it has, except that we never get to see that rotation.
Therefore, think now of a compass resting on a tabletop. A magnetised ball rolls around it with the compass's needle pointing to the ball at all times. When the ball has gone completely around the compass, has it also gone around the needle?
Also, did you know that the rear end of a sliding glacier coming down a mountain moves faster than its front end (with respect to a fixed point of reference)? But how can that be since it's the same glacier? It's like saying the rear end of a train is moving faster than its front end.
DEAR MS
(The Try-Another-Day repeat problem was: &"A perfect sphere made of chalk rolls on a flat surface at constant speed. The chalk is transferred from the sphere to the surface at a uniform rate. If the sphere rolls in a straight line until there is nothing left of it to roll, approximately what shape will be seen on the flat surface?" Mercifully, more than 20 people responded this time with some pretty sharp observations too, as you can see for yourself below. - MS)
I-Saw-Sillies-Dept:
The shape seen on the flat surface will be an isosceles triangle. The base of this triangle will be the diameter of the sphere, as will be the height. Meherab Saher, meherab@meherab.com 
The figure I get in my mind when I think of that situation is an isosceles triangle but I'm guessing it isn't that simple. Probation Paul, prbtnpl@gmail.com (But PP, sometimes life is actually &that simple - MS) 
The shape will be triangular because if it starts transferring from a point, its width will keep increasing, resulting in the width of the shape to increase. In other words, it's just the triangle being formed from a vertex. -Mohammed Hani Sheik, &hani13may@yahoo.com 
(The other problem was: "A sundial has the fewest moving parts of any timepiece. Which has the most?" - MS)
Watch-That-Part-Dept:
The most moving parts in my opinion would be in an hourglass (sand particles).
Tholepin Chandrashekhar, &tholeti.cs@gmail.com
Going by the era which had sundials as time-pieces, then an hourglass should qualify as the timepiece with the most moving parts (or particles); i.e., sand. But this morning when I was shaken out of my slumber, I could not help but think that an alarm clock ringing is the timepiece with the most moving (vibrating) parts.   Saifuddin S F Khomosi, saif_sfk@hotmail.com
 
ENDGAME
A snakebite antidote consists of two bottles labelled A and B, containing three tablets each. The snake-bitten victim has to take one tablet from bottle A and one tablet from bottle B simultaneously and has to repeat the same dosage two more times with an interval of ten minutes. He takes a tablet from bottle A and then shakes a tablet out from bottle B but, unfortunately, two tablets fall out. Now he has three tablets in his hand and they look identical. He cannot tell which tablet is A and which tablet is B. He is desperate; if he does not take the tablets exactly as prescribed, it will be fatal. How can the man save himself?
Submitted by Dr P Gnanaseharan, gnanam.chithrabanu@gmail.com
(To get in touch with Mukul, mail him at mukul.mindsport@gmail.com)
 
 

• Mindsport