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Ball Bearings

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.

Far Horizon

An observer is on top of a lighthouse. How far from the foot of the lighthouse is the horizon that the observer can see?

Air Routes

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.

What's That Graph?

Age 14 to 18 Challenge Level:


Here are some graphs of physical processes.





Can you suggest plausible processes that could have given rise to each graph?

Now click on the link below to see eight processes that give rise to the graphs.
Can you match each process to a graph?






Can you suggest equations that could model each of these processes?

Now click on the link below to see eight equations.
Can you match each equation to the graphs and related processes?






Can you determine values for the constants A, B and C for each equation? For some, you will need to make some assumptions.