51) A simple pendulum of length 1 has an energy E when its amplitude is A. If its amplitude is increased to 2 A, the energy becomes

52) If the kinetic energy and potential energy of a simple harmonic oscillator of amplitude A are both equal to half the total energy, then the displacement is equal to

53) The ratio of kinetic energy and potential energy of a simple harmonic oscillator, at a displacement equal to half its amplitude is given by

54) A simple pendulum of length / has an energy E, when its amplitude is A. If the length of pendulum is doubled, the energy will be

55) Time period and length of a seconds pendulum respectively are