When a force is applied to a spring, the spring extends by 12cm. The spring has a spring constant of 25 N/m. Calculate the force applied to the string in N.

The equation needed in this scenario is: Force Applied (F) = Spring Constant (k) x Extension (x). This will most likely be given to the student on the data sheet for most exam boards. Firstly, you must convert the extension into metres to ensure that our answer is in newtons. You would do this by dividing the number by 100, therefore the extension is 0.12m. We can now substitute the numbers into the equation: F=kx=0.12x25=3 So the force applied is 3.0N.