What will be the work done in dropping an object a) +ve b) -ve c) zero
in advance..

In order to do work, the force vector must be question 1 options: in a different direction than the acceleration vector. in a different direction than the displacement vector. in the same direction as the displacement vector and the motion. in the same direction as the acceleration vector.

An object is kept at 45 m high and how much time will it take to reach the ground

The energy of a photon is equal to (what) times (what) of the photon.