Exercise 2: sample answer

With the pedals fixed directly to the front axle, one turn of the pedals gave one turn of the wheel, so the distance covered per pedal turn equalled the wheel's circumference. The only way to go further, and so faster, for the same effort was to make the front wheel bigger. There was no gearing to change this ratio, so makers kept enlarging the front wheel, which produced the high wheeler (Chapter 4).