How strong is a tesla and how strong is a newton?

-- "Tesla" is a unit for the strength of a magnetic field.

The Earth's magnetic field at the surface ... the one that makes
compasses work ... averages roughly 45 microteslas. 

So 1 Tesla = somewhere around 20,000 times the magnitude
of Earth's magnetic field at the surface.

There's a smaller, more convenient unit, called the 'Gauss'.
1 Tesla = 10,000 Gauss.  The Earth's magnetic field ranges
between 0.25 to 0.65 Gauss at various places on the surface.

-- Newton is a unit of force, equal to about 3.6 ounces. 
1 pound of force is about 4.45 newtons.

Electoral current force mechanical advantage if the wheel and axle is 2 n and the output force is 20 n