For a hollow cylinder and a solid cylinder rolling without slipping on an inclined plane, then which of these reaches earlier

As shown in the figure at point O a mass is performing vertical circular motion. The average velocity of the particle is increased, then at which point will the string break

If $$\overrightarrow F = \left( {60\widehat i + 15\widehat j - 3\widehat k} \right)$$ N and $$\overrightarrow v = \left( {2\widehat i - 4\widehat j + 5\widehat k} \right)$$ m/s, then instantaneous power is

For a planet having mass equal to mass of the earth but radius is one fourth of radius of the earth. Then escape velocity for this planet will be