An arrow was shot horizontally at a speed of 40 m/s from a bow held 1.5 meters above the ground. it misses the target and hits the ground how much time does it take the arrow to hit the ground?

If we can ignore any effects of air resistance ... and we always do ... then it
makes no difference what its horizontal speed was, or whether it had any
at all.  It hits the ground in the same time as an arrow that just dropped from
the bow to ground.

The distance an object falls from rest in ' T ' seconds, on account of gravity, is

         D  =  1/2 G T² .            ('G' is the acceleration of gravity, 9.8m/s² )

This arrow falls 1.5 meters,and 1/2 G is  9.8/2  =  4.9 m/s² .

       1.5 m  =  4.9 m/s²  T²

Divide each side by  4.9 m/s² :    (1.5 / 4.9)  sec²  =  T²

Take the square root of each side:    T  =  square root of (1.5/4.9) = 0.553 sec

Neptune is the eighth planet from the sun. it was the first planet to get its existence predicted by  mathematical calculations  before it was actually seen through a telescope on sept. 23, 1846. irregularities in the orbit of  uranus  led french astronomer alexis bouvard to suggest that the gravitational pull from another celestial body might be responsible. german astronomer johann galle then relied on subsequent calculations to   spot neptune via telescope. previously, astronomer galileo galilei sketched the planet, but he mistook it for a star due to its slow motion. in accordance with all the other planets seen in the sky, this new world was given a name from greek and roman mythology — neptune, the roman god of the sea.