Physics Units

An important part of physics problems is units of measurement. These can easily be handled by multiplying the number by the conversion factor that converts the unit to SI (metric) units. For example, an inch is 0.0254 meter, so 40 inches is 1.016 meter.

(phys '(what is the area of a circle
         with radius = 40 inches))

(calculate area (object circle (radius 1.016)))

3.2429278661312964

The calculate form can accept a multiply by a factor, allowing units for the goal of the calculation:

(phys '(what is the area in square-inches
        of a circle with radius = 1 meter))

(calculate (* area 6.4516E-4)
           (object circle (radius 1.0)))

4869.478351881704