Question 53
A small ring of negligible thickness and radius 2cm moves on a bigger ring of radius 10 cm. How many rotations will the small ring take on the bigger ring to make a complete round ?
Solution
The perimeter of the smaller ring is $$4\pi\ $$ . The perimeter of the larger ring is $$20\pi\ $$
As we can clearly see, it will take 5 rotations of smaller ring to completely cover the larger circle.
