A cone filled with water is revolved in a vertical circle of radius $$4 \mathrm{~m}$$ and the water does not fall down. What must be the maximum period of revolution?
Consider a rod of mass $$M$$ and length $$L$$ pivoted at its centre free to rotate in a vertical plane. The rod is at rest in the vertical position. A bullet of mass $$M$$ moving horizontal at a speed $$v$$ strikes and gets embedded in one end of the rod. The angular velocity of the rod just after the collision will be
In a cathode ray tube, a potential difference of 3000 volts is maintained between the deflector plates whose separation is $$2 \mathrm{~cm}$$. A magnetic field of $$2.5 \times 10^{-3} \mathrm{~Wb} / \mathrm{m}^2$$ at right angles to electric field gives no deflection of the electron beam, which received an initial acceleration by a potential difference of $$10000 \mathrm{~V}$$. Calculate $$(\mathrm{e} / \mathrm{m})$$ of an electron.
A wire of cross-section $$A$$ is stretched horizontally between two clamps located $$2 l$$ metre apart. A weight $$w \mathrm{~kg}$$ is suspended from the mid-point of the wire. If the mid-point sags vertically through a distance $$x<1$$, the strain produced is