The wheels of this penny farthing have diameters 34 cm and 136 cm respectively (including the tyres). Determine the circumference of each wheel. Over a 1 km distance, the number of revolutions turned by the wheels is closest to:

Experiment

The relationship between the diameter D and the circumference C of a circle is C = D. So you can use a wheel of your (penny-farthing!) bicycle to calculate the value of .

(a) Try measuring C and D directly to determine .

(b) A better plan is to ride your bike over a measured distance and count the number of revolutions of the wheel. Explain.
The old penny-farthing bicycle was named after the British coins, the penny and the farthing. The small farthing was worth a quarter of a penny.
 

No, these are not correct.
The right answer requires
a careful calculation!

Try again.


These values are
rather too large.
Think about this
a bit more,
and try again.