How far does a bullet travel horizontally before gravity has an effect and takes over Is Newtons law correct that the bullet will hit the ground at the same time if it were simply dropped?

Answer 1

Gravity has an effect the instant the bullet leaves the barrel. The bullet starts to fall towards the earth at the same rate as the dropped bullet.

However, (assuming the ground follows the curve of the earth, or you are shooting over water) the dropped bullet will hit the ground/water first. The reason is that the as the fired bullet falls the ground is receding away from it (the curve of the earth).

The extreme example of this is: the bullet is fired fast enough that as it falls, the curve of the earth is 'falling' continuously away below it; we would say this bullet is now in orbit around the planet.

However, if the ground you are shooting over is 'flat' (i.e. flat like a ruler, NOT following the curve of the earth) then: yes, the two bullets will hit the ground at the same time.

Answer 2

Gravity always affects the motion of objects on Earth. It is true that a bullet dropped and a bullet fired from a gun at exactly the same moment will hit the ground simultaneously, although this is not a specific law attributed to Isaac newton. However, how far a bullet will travel horizontally before it hits the ground depends on its initial velocity and air resistance.

To understand this think of the velocity of the bullet having two components: one horizontal and the other vertical. The horizontal velocity is entirely independent of gravity. So, ignoring air resistance, the bullet will continue to travel at this velocity in a horizontal orientation unless it collides with something or a force begins to act on it. The vertical velocity is affected by gravity. So, the bullet accelerates towards the ground under the force of gravity.

Thus, a bullet fired on Earth has whatever horizontal velocity imparted to it by the force of the gun initially and an initial vertical velocity of 0 m/s^2. So, the bullet moves through a parabolic trajectory until it hits the ground. The bullet dropped on Earth moves straight down until it hits the Earth. And since the two bullets have the same downward acceleration they hit the ground at the same time (provided they were dropped and fired at the same time).

Answer 3

that is true