Physics-Oscillatory Problem!?

Question

Two geekie physics students with a combined mass of 146 kg jump into their old car to run out for some late night pizza. The distance between the front and back axles of the car is 2.7 m. When they get in the car, the springs compress a total of 8.9 cm. On their way to the Pizza Hut, when they go over a bump, the car oscillates up and down with a period of 1.7 seconds.

** What is the mass of the car?

Answer 1

Apparently we are ignoring any pitching motion due to their getting in the car and due to the bump, since you'd need to know a lot more about mass distribution if it was pitching. So we're only considering vertical movement and the distance between axles is irrelevant. I'm assuming "a total of 8.9 cm" means the sum of the 4 spring deflections, so their average deflection is 2.225 cm. If it actually means the average deflection, then k and m are 1/4 what you'll get with the following calculations. Stiffness k (of the 4 springs in parallel) in n/M = 146*g/.02225. Natural radian frequency w = sqrt(k/m), so m = k/w^2 = k/(2*pi/1.7)^2. (That's the total m; mass of car = m-146.)
This was not a well-phrased question, because "a total of 8.9 cm" also could mean 8.9 cm from their no-load length (and thus due to the weight of the car and the students). However this would result in an insoluble problem.
BTW, why are they geeky? Did they figure all this out before me?

Answer 2

Here are the solutions that I received: a) three.55784 b) zero.01687J c) zero.375m/s2 For angular frequency i used the system: w=rectangular root of (g/l) g=10m/s2 l=zero.seventy nine m For the mechanical vigor we all know that on the maximum pointof the swing, the kinetic vigor is zero J. So we stick that into the system and uncover the whole mechanical vigor which might be the gravitational skills vigor on the maximum amplitude of the pendulum. U then must calculate how prime the pendulum is above the reference factor of 0 (on the lowest factor of the swing) use phythagorous conception to uncover this : h=zero.78297 m. Use this within the system Epg= mgh. At the bottom factor of the pendulum we are saying that the gravitational skills vigor is 0 therfore at this factor, all of the mechanical vigor within the method is kinetic vigor. We equate those and transpose the equation for pace. The reply is V=zero.375m/s2