Chis Petrie’s “grandad” problem
Many yeas ago, his grandad suggested to the young Chris Petrie
that he calculate the angle of the dangling rod
in the diagrem.
It is rumoured that the grandad added that it would keep Chris
quiet on a rainy day.
Was this a case of “Spare the rod and spoil the child”?
In order to make things easy, we are to assume that the two strings are weightless,
and the magic knots allow complete freedom or movement.
In order to make things difficult, all four lengths in the diagram are in general different.
Pray for fine weather.