Question

purpose of using different sizes of axles

Answer 1

The mechanical advantage of a simple machine like the wheel and axle is computed as the ratio of the resistance to the effort. ... In this manner, the size of the wheel may be increased to an inconvenient extent. In this case a system or combination of wheels (often toothed, that is, gears) are used.

Answer 2

The mechanical advantage of a simple. machine like the wheel and axle is computed as the ratio of the resistance to the effort. .

.. In this manner, the size of the wheel may be increased to an inconvenient extent.

In this case a system or combination of wheels (often toothed, that is, gears) are used