$(a)$ The potential energy of a freely falling object decreases progressively. Does this violate the law of conservation of energy? Why?
$(b)$ An object is dropped from a height $h$. When is its
$(i)$ potential energy maximum?
$(ii)$ kinetic energy maximum?

(N/A) No,the total energy of the body is conserved. As a body falls down,its height from the ground decreases,and hence its potential energy decreases. Simultaneously,its velocity and kinetic energy increase. The decrease in potential energy is exactly equal to the gain in kinetic energy. Thus,the sum of potential energy and kinetic energy (mechanical energy) remains constant at any instant of time.
$(b)$
$(i)$ Potential energy is maximum at the initial height $h$,where the object is at rest.
$(ii)$ Kinetic energy is maximum at the ground level,just before the object hits the surface,as the velocity is highest at this point.