What force is required to stretch it by this amount? Answer in units of N.

Question

A load of 35 N attached to a spring hanging vertically stretches the spring 3.5 cm. The spring is now placed horizontally on a table and stretched 11 cm. What force is required to stretch it by this amount? Answer in units of N.

Answer 1

Assuming the spring itself has no weight.

The force is proportional to the stretch, so write a proportion:

F / 35N = 11cm / 3.5cm

F = 110N

A slightly longer way of solving is to find the spring constant first:

F = kx

k = F/x = 35N / 3.5cm = 10 N/cm

The horizontal force follows the same formula but with the new stretch:

F = kx = (10 N/cm)(11 cm) = 110N