If the radius of the axle is 5" and the radius of the wheel is 8", what is the mechanical advantage of this wheel and axle configuration?

The mechanical advantage of a wheel and axle lies in the difference in radius between the inner (axle) wheel and the outer wheel. But, this mechanical advantage is only realized when the input effort and load are applied to different wheels. Applying both input effort and load to the same wheel results in a mechanical advantage of 1.