S1: On increasing the temperature of solids, the kinetic energy of the particles increases. P: A stage is reached when the solid melts and is converted to a liquid. Q: Due to the increase in kinetic energy, the particles start vibrating with greater speed. R: The particles leave their fixed positions and start moving more freely. S: The energy supplied by heat overcomes the forces of attraction between the particles. S6: The temperature at which a solid melts to become a liquid at the atmospheric pressure is called its melting point. Find the correct sequence of P, Q, R and S.