Recent content by eladtan

The force the car feels is the total force from all of the four springs. If you write down Newton's second law: m\ddot{x}=-4kx From this equation it is obvious that the relevant frequency is \omega=\sqrt{4k/m}

In your problem the scales show that the mass "weighs" 4.35N, this is the measure of the normal force experienced by the mass. The normal force is given by: $F_N=F_g-F_b=4.9-F_b=0.55N\Rightarrow F_b=0.55N$. The second part seems correct.