What should be the spring constant k of a spring designed to bring a 1200 kg car to rest from a speed of 95 kph so that the occupants undergo a maximum acceleration of 4.0 g?

To find the spring constant k, we first calculate the deceleration needed to bring the car to rest from 95 kph using a = (v^2 - u^2) / (2 * s), where u is initial velocity, v is final velocity, s is displacement. Converting 95 kph to m/s, we get u = 26.39 m/s. We then use the maximum acceleration of 4.0 g to find the deceleration, a_max = 4.0 * 9.81 m/s^2. Finally, we can calculate the spring constant k by equating F_spring = m * a = k * x, where x is the displacement and solve for k.