Water drops are falling at regular interval of 1 second from a tap when first drop touches the ground at that time the fourth drop just about to fall find the height of the third drop from the ground. given the height of the tap is 5 M from the ground.
I think the question is incomplete. Either of the two conditions should be given:
I agree with @Sanchit_saxena.
If you assume all droplets are experiencing a constant force (mg) then it is an easy Kinematics question, otherwise viscous force will work.
The point is , that if only gravity acts , then the problem is over specified and also, the given height of tap doesn't follow g=10, instead from given 5 m we can conclude that g' = 0 625m/s^2