A particle completes 2 revolutions in a circular path of radius 3 cm. The angular displacement of the particle will be (in radian)

A car is travelling at 40 m/s on a circular path of radius 40 m. It is increasing its speed at the rate of $2\ \text{m/s}^2$. Its net acceleration is (in $\text{m/s}^2$) nearly

A particle is performing U.C.M. along a circle of radius $R$. In half the period of revolution, its displacement and distance covered are respectively

A stone of mass $40$ g is tied to a light inextensible string of length $50$ cm and whirled in a vertical circle at the rate of $30$ revolutions per minute. The tension in the string when it is at the lowest point of the circle is
(Take gravitational acceleration, $g = 10\,\text{m/s}^2$ and $\pi^2 = 10$)