Spring rate 50 N / m. What force must be applied to stretch this spring by 4 m?

The force required to stretch the spring by 4 m is equal to the spring force:

F = F = k * ∆l, where k is the stiffness of the spring (k = 50 N / m); ∆l is the amount of deformation (elongation) of the spring (∆l = 4 m).

Let’s calculate the required force:

F = F = k * ∆l = 50 * 4 = 200 N.

Answer: To stretch the spring by 4 m, a force of 200 N must be applied.