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.
Bricks are 20cm long and 10cm high. How high could an arch be built
without mortar on a flat horizontal surface, to overhang by 1
metre? How big an overhang is it possible to make like this?
The shortest path between any two points on a snooker table is the straight line between them but what if the ball must bounce off one wall, or 2 walls, or 3 walls?
The following solution was sent in by
Thomas from Dalton Primary School, New York. If you repeated
Thomas's experiment with the same simulation parameters you would
get different results. Can you think why? It is because the results
depend on probabilities. To get reliable results that we can base
decisions on we need to find the average (or mean) results from
many repetitions of the same experiment with exactly the same
Thomas's results are interesting because they
show very different outcomes according to whether the sick people
circulate in the village, or stay at home or are put in total
isolation. Lewis from Highcliff Primary School also says that
isolation is a good policy but when do you think it is advisable