Answer to Question #181751 in Physics for Arvin Shopon

Question

There is one spring for each wheel of the car. The car enthusiast is planning to change the springs of his car. What should be chosen as the spring constant for new springs when you want an empty car to press the springs into a pile of 65 mm? The unladen mass of the car is 1470 kg and its weight is assumed to be evenly distributed on each wheel.

Answer 1

We have four springs of stiffness k 'connected' in parallel. Find an equivalent of n of them so they can be replaced by a 'single' equivalent spring:

$$K=nk.$$

By Hooke's law and equilibrium of forces:

$$mg=Kx, \\\space\\ K=\frac{mg}{x}=nk, \\\space\\ k=\frac{mg}{nx}=55408\text{ N/m}.$$