SI units of force:

           SI unit of force is newton (N).

Newton (1 N):

           One newton (1 N) is the force that produces an acceleration of $1 \: ms ^{-2}$ in a body of mass of 1 kg.

        Thus, a force of one newton can be expressed as

$1 \: N \: = 1 \:kg \: \times 1 \:ms^{-2}$

Or  $1 \: N \: = 1 \:kgms^{-2}$