For the pivoted slender rod of length $l$ as shown in figure, the angular velocity as the bar reaches the vertical position after being released in the horizontal position is

A $2 \,{kg}$ steel rod of length $0.6\, {m}$ is clamped on a table vertically at its lower end and is free to rotate in vertical plane. The upper end is pushed so that the rod falls under gravity, Ignoring the friction due to clamping at its lower end, the speed of the free end of rod when it passes through its lowest position is $\ldots \ldots \ldots \ldots \,{ms}^{-1}$. (Take $g = 10\, {ms}^{-2}$ )

A rod of length $50\,cm$ is pivoted at one end. It is raised such that if makes an angle of $30^o$ fro the horizontal as shown and released from rest. Its angular speed when it passes through the horizontal (in $rad\,s^{-1}$ ) will be $(g = 10\,ms^{-2})$

A rod of length $1\,meter$ is standing vertically, when its other end touches the ground without slipping then the speed of other end will be

Two discs of moments of inertia $I_1$ and $I_2$ about their respective axes (normal to  the disc and passing through the centre), and rotating with angular speed $\omega _1$ and $\omega _2$ are  brought into contact face to face with their axes of rotation coincident. What is the  loss in kinetic energy of the system in the process ?

Two coaxial discs, having moments of inertia $I_1$ and $\frac{I_1}{2}$ are a rotating with respectively angular velocities $\omega_1$ and $\frac{\omega_1}{2}$, about their common axes. They are brought in contact with each other and thereafter they rotate with a common angular velocity. If $E_f$ and $E_i$ are the final and initial total energies, then $(E_f -E_i)$ is