Period of Oscillation?

Question

The body of an automobile has a mass of 750 kg. During factroy assembly it was noted that the auto body compresses the suspension system 10 cm. Find the period of oscillation when the car hits a bump.

Answer 1

assume spiral spring, F=kx or k=F/x...period of oscillation, T=(2pi)sqrt(m/k)=(2pi)sqrt(mx/F) where F=mg.  so T=(2pi)sqrt(x/g)=(2pi)sqrt(.1/9.81)=.634...

Answer 2

W=k*dl-->k=W/dl-->k=750N/.10m=7500N/m

W=m*g-->m=W/g-->m=750kg/9.8m/s^2=76.5k...

T=2*3.14*sqr(m/k)-->T=0.63s