The radius of a curved road is $R$,and the width of the road is $b$. The outer edge of the road is raised by $h$ with respect to the inner edge so that a car with velocity $V$ can pass safely over it. The value of $h$ is ($g =$ acceleration due to gravity).

The maximum speed of a car on a road-turn of radius $30\, m$,if the coefficient of friction between the tyres and the road is $0.4$,will be .......... $m/s$. (in $.84$)

$A$ car is moving on a circular level road of curvature $300\,m.$ If the coefficient of friction is $0.3$ and acceleration due to gravity is $10\,m/s^2,$ the maximum speed the car can have is ........ $km/hr.$

$A$ circular racetrack of radius $300 \; m$ is banked at an angle of $15^{\circ}$. If the coefficient of friction between the wheels of a race-car and the road is $0.2$,what is the
$(a)$ optimum speed of the racecar to avoid wear and tear on its tyres,and
$(b)$ maximum permissible speed to avoid slipping?

$A$ motorcyclist moving with a velocity of $72\, km/h$ on a flat road takes a turn at a point where the radius of curvature of the road is $20\, m$. The acceleration due to gravity is $10\, m/s^2$. In order to avoid skidding,he must not bend with respect to the vertical plane by an angle greater than

$A$ body of mass $M \text{ kg}$ is at the top point of a smooth hemisphere of radius $5 \text{ m}$. It is released to slide down the surface of the hemisphere. It leaves the surface when its velocity is $5 \text{ m/s}$. At this instant, the angle made by the radius vector of the body with the vertical is (Acceleration due to gravity $g = 10 \text{ m/s}^2$) (in $^{\circ}$)