A hunter aims a gun at a monkey hanging from a tree some distance away. The monkey drops from the branch at the moment he fires the gun hoping to avoid the bullet. Explain why the monkey made a wrong move.

Explanation

Let the bullet if fired with an angle `alpha` and distance from hunter`s rifle to monkey=x vertical component of velocity `v_(xy)=v sin alpha` when exactly aimed at monkey `s_y=v sin alpha`
t=h

But due to acceleration due to gravity
`h_1=u sin alphat-1/2g t ^2=h-1/2g t ^2to (1)`
So bullet passes through a height of `1/2 g t^2` below the monkey.
But when the monkey is falling freely height of fail during time `t=1/2 g t^2`
So new height is `h-1/2g t ^2to(2)`
From equations (1) & (2) `h_1` is same i.e., if the monkey is dropped from the branch bullet will hit it exactly.