What's the formula of tensile force and elongation of physics grade one?

What's the formula of tensile force and elongation of physics grade one?

You're talking about Hooke's law. Hooke's law
Within the elastic limit, the elastic force of a spring is directly proportional to its deformation (elongation or compression value)
F = k · X "F", which means the elastic force "X" of the spring, is the length of spring extension or shortening
"K" is the stiffness coefficient of the spring. The international unit is n / m