P is a point on the circumference of a circle radius r which rolls,
without slipping, inside a circle of radius 2r. What is the locus
The coke machine in college takes 50 pence pieces. It also takes a certain foreign coin of traditional design...
What happens to the perimeter of triangle ABC as the two smaller
circles change size and roll around inside the bigger circle?
A bicycle passes along a path and leaves some tracks.
Is it possible to examine the curve of the individual tracks
(both tyres have identical tread) and from them say which track was
made by the front wheel and which by the back wheel?
Is it possible to say in which direction along the path the
bicycle was travelling ?