<<PhysicalConstants`
<<Units`

Convert[((Kilo Gram Meter)/(Hour^2)),Newton]

Convert[((2 Nano Coulomb)(0.4 Nano Coulomb))/(4 π VacuumPermittivity (((4 Centi Meter))^2)), Micro Newton]

Convert[((((((2-0.4)/2)) Nano Coulomb))^2)/(4 π VacuumPermittivity (((4 Centi Meter))^2)), Micro Newton]

q=4.0 Nano Coulomb;
a= 15.0 Centi Meter;
E1=Convert[(q/(4 π VacuumPermittivity (a^2))),Newton/Coulomb]
E3=Convert[(q/(4 π VacuumPermittivity 2(a^2))),Newton / Coulomb]
Et={E1+(E3/(Sqrt[2])),E1+(E3/(Sqrt[2]))}

Convert[(Coulomb/VacuumPermittivity) (Meter/(Meter^3)),Volt/Meter]