What force must be applied to a spring with a stiffness of 40 N / m in order to stretch it by 5 cm?

The force of elasticity, which is necessary to stretch the spring, is calculated by the formula:

Fcont. = k * ∆l, where k is the stiffness of the spring (k = 40 N / m); ∆l is the amount of deformation of the spring (elongation of the spring, ∆l = 5 cm = 0.05 m).

Let’s calculate the elastic force:

Fcont. = k * ∆l = 40 * 0.05 = 2 N.

Answer: To stretch the spring by 5 cm, you must apply a force equal to 2 N.