In `PCl_5` the two axial bonds are longer than equitorial bonds why?

Which of the two C-CI bond shown below will have more dipole moment and why?

It is easier to revolve a stone by attaching it to a shorter string rather than- to a longer one. Why?

A solid sphere rolls down two different inclined planes of the same heights but different angles of inclination, (a) Will it reach the bottom with the same speed in each case? (b) Will it take longer to roll down one plane than the other? (c) If so, which one and why?

Although geometry of NH_3 and H_2O molecules are distorted tetrahedral, bond angle in water is less than that of ammonia . Discuss.

Give one chemical reaction to show that all the bonds in PCI_5 molecules are not equivalent?

Two open pipes of different lengths are producing their fundamental tones simultaneously and the number of beats per second is 5.if the shorter pipe has fundamental frequency 250 Hz,what is the length of the longer pipe?(velocity of sound = 340m/s)