A particle performs uniform circular motion with an angular momentum $L.$ If the angular frequency of the particle is doubled and kinetic energy is halved, its angular momentum becomes
$4L$
$2L$
$L/2$
$L/4$
A flywheel is in the form of solid circular disc of mass $72\,\, kg$ and radius of $0.5\,m$ and it takes $70\, r.p.m.$ , then the energy of revolution approximately is ....... $J.$
A ring of mass $M$ and radius $R$ is rotating about its axis with angular velocity $\omega $. Two identical bodies each of mass $m$ are now gently attached at the two ends of a diameter of the ring. Because of this, the kinetic energy loss will be
$A$ man, sitting firmly over a rotating stool has his arms streched. If he folds his arms, the work done by the man is
A thin hollow cylinder open at both ends:
$(i)$ Slides without rotating
$(ii)$ Rolls without slipping, with the same speed
Starting from the rest, at the same time, a ring, a coin and a solid ball of same mass roll down an incline without slipping .The ratio of their translational kinetic energies at the bottom will be