The speed of a car increases uniformly with time from $50 \mathrm{km} / \mathrm{h}$ at $A$ to $100 \mathrm{km} / \mathrm{h}$ at $B$ during $10 \mathrm{sec}$ onds. The radius of curvature of the hump at $A$ is $40 \mathrm{m} .$ If the magnitude of the total acceleration of the mass center of the car is the same at $B$ as at
$A,$ compute the radius of curvature $\rho_{B}$ of the dip in the road at $B$. The mass center of the car is $0.6 \mathrm{m}$ from the road.