If a is the radius of the axle, b the radius of each ball-bearing, and c the radius of the hub, why does the number of ball bearings n determine the ratio c/a? Find a formula for c/a in terms of n.
An observer is on top of a lighthouse. How far from the foot of the lighthouse is the horizon that the observer can see?
Find the distance of the shortest air route at an altitude of 6000
metres between London and Cape Town given the latitudes and
longitudes. A simple application of scalar products of vectors.
The 100m sprint isn't the only event where humans move fast! Here are some suggestions of other speedy competitors you could consider:
A cyclist in a sprint
A wheelchair racer in the Paralympics
A diver as he enters the water
A long jumper as he takes off
or perhaps including the Winter Olympics too...