1. The problem statement, all variables and given/known data A car driver updates the springs of a car by replacing the old springs with stiffer ones. The old springs give an amount of 8 cm when under the car, and their length when not under the car is 29 cm. The spring constant of the new springs is 30 % greater than that of the old springs. How long do the new springs have to be in order the car to be located the same distance from the ground with the new springs as with the old springs? k = the spring constant of the old springs x = the length of the new spring(s) when under the car xnorm = the normal ("unloaded") length of the new spring(s) xreq = the required length of the new spring(s) 2. Relevant equations Hooke's law: F = kx 3. The attempt at a solution I have no idea. I have trouble formulating the equation. k * (29 cm - 8 cm) = 1.3k * x k * 21 cm = 1.3k * x || / 1.3k k * 21 cm / 1.3k = x x ≈ 16.153 cm 29 cm / 21 cm = xnorm / 16.153 cm 1.381 = xnorm / 16.153 cm || * 16.153 cm xnorm ≈ 22.307 cm 22.307 cm / 16.153 cm = xreq / 21 cm 1.381 = xreq / 21 cm || * 21 cm xreq = 29.001 cm ????? It's the same as the original!