The force required to keep a body in uniform circular motion is

A car is moving with high velocity when it has a turn. A force acts on it outwardly because of

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 .......... $m/sec$

A disc rotates about its axis of symmetry in a hoizontal plane at a steady rate of $3.5$ revolutions per second. A coin placed at a distance of $1.25\,cm$ from the axis of rotation remains at rest on the disc. The coefficient of friction between the coin and the disc is $(g\, = 10\,m/s^2)$

A railway line is taken round a circular arc of radius $1000\ m$, and is banked by raising the outer rail $h\  m$ above the inner rail. If the lateral force on the inner rail when a train travels round the curve at $10 \ ms^{-1}$ is equal to the lateral force on the outer rail when the train's speed is $20\  ms^{-1}$. The value of $4g\  tan\theta$  is equal to : (The distance between the rails is $1.5 \  m$).

Assuming the coefficient of friction between the road and tyres of a car to be $0.5$, the maximum speed with which the car can move round a curve of $40.0\, m$ radius without slipping, if the road is unbanked, should be ......... $m/s$