Question

What is force constant ND give unit

Answer 1

Force constant is defined as the applied force if the displacement in the spring is unity. It is denoted by k.

its unit is:
  k units = Newton/meter = kg-m/sec^2//m = kg/sec^2 

Answer 2

Spring constant or force constant is defined as the applied force if the displacement in the spring is unity. It is denoted as k.
formula is :
F=kx.
k=F/x
unit is:
Newton/ meter = kg/sec^2.