F is the symbol for Force! The units of force are newtons or because force is made up of mass (kg) x acceleration (meters/second squared) we can say the units for force is just a blend of these.
So units for force is newtons or kg per meter squared.
Both of these units are correct for force.
M is the symbol for Mass! The units for mass are kg
A is the symbol for acceleration, the units for acceleration are meters per second per second ( ms^2)
