Hanging on a branch of a tree, a monkey sees a hunter aiming a gun at him. The monkey lets go of the branch at the exact same time the bullet is fired. Explain why the bullet hits the monkey.

This question is also applicable to physics mechanics.

Many would think the bullet will hit the monkey because it is travelling much faster than him. However, modelling the monkey as a particle and ignoring any affects of air resistance, and assuming that the bullet was fired perfectly horizontally, both the monkey and the bullet will be falling towards the ground at the same rate, meaning that the monkey and the bullet will collide on the ground. The monkey would have escaped the shot had it trusted the effects of gravity and held onto the branch. The bullet's horizontal speed though vast, does not affect it's vertical drop, as two perpendicular components (in this case: weight and trajectory) do not affect each other.

Reasons for assumptions:

1) modelling the monkey as a particle means that it has no considerable height. This is because in a realistic situation if the shooter is too close, even if the monkey doesn't let go of the branch, a part of his body will incur the hit. It won't be the exact same spot as aimed because the bullet would have dropped height (even if it's unnoticeable). If the distance is sufficient, it would have had time to to drop enough to miss its entire body.

2) Air resistance plays a significant role in how object free fall, though all falling objects should in theory fall at the same rate (9.81ms^-2), air resistance is proportional to the area of the object, as demonstrated by Galileo's experiment. Removing air resistance means a feather and a cannon ball would fall at the same rate, and so would a bullet and a monkey. However, the monkey has a larger surface area and would fall at a slower rate than the bullet when air resistance is not removed.

3) If the bullet is not fired perfectly horizontal, it would have other components playing a part, alongside gravity. The monkey letting go of the branch is his submission to gravity and no external factors are playing a part. However, if a bullet is fired at even the slightest angle, it would have a slight vertical component either working alongside or opposing gravity meaning that the bullet would either take a parabolic path if fired upwards or would be faster than gravity if fired downwards.