A car travels on a circular racetrack of radius 50 m, which is banked at an angle θ. If the car travels at a speed 10 ms^-1, then the wear and tear…

A car travels on a circular racetrack of radius $\displaystyle 50$ m, which is banked at an angle $\displaystyle \theta$. If the car travels at a speed $\displaystyle 10 \mathrm{~ms}^{-1}$, then the wear and tear on its tyres is minimum. Taking the acceleration due to gravity to be $\displaystyle 10 \mathrm{~ms}^{-2}$, the value of $\displaystyle \theta$ is :