if one were to leap out off something very high would they constantly keep a forward motion or would gravity..

Question

eventually pull them straight down

Answer 1

There are two kinds of answers to this.
1. You are on a planet like Earth with gravity and air:
As speed increases, it is the air that makes increasing speed more difficult. That is why even though gravity is always pulling you down, you - the theoretical average person - will reach a top speed of around 150 miles per hour instead of increasing speed all the way down. This resistance is called drag. Drag will also affect the forward motion that you had when you jumped forward. It is not as strong as it is at 150 mph when it equals 1 G. But it is there and will gradually slow your forward motion to zero.

If there was no gravity, and you jumped off a high place that was surrounded by air, you would eventually just stop in mid air. You could swim through the air using just your arms and legs like in water! Just look closely at movies from the ISS. (International Space Station) Strange things happen there because of the low gravity.

2. You are on a place like the moon with gravity but no air:
In this case there is no drag to slow either your forward motion nor your constant acceleration. You would eventually hit the ground with the acceleration of gravity and also the speed you had in your leap off the tall place.

;-D In the first case, a parachute could save your life. In the second case you will need a bungee cord and a space suit!

Answer 2

Newton's first law of motion, an object would continue to move with a constant velocity unless acted upon by an unbalanced force. Gravity work perpendicular to the forward motion, so it would have no effect on the forward motion.

In a practical real life example an object would hit the ground before air resistance would slow it down. This is the reason artillery works. An angle is decided upon so the forward motion will carry a shell a specific amount of metres before falling on top of an enemy position.

Answer 3

Reality and ideal physics problems are totally different.

Ideally you leap off something very high and your forward
motion continues uniformly as you accelerate downward
under the influence of gravity.

In reality, updrafts, air density, friction, your clothes, the way
your body is tilting all affect your motion in both horizontal
and veritical directions. You could get more accurate if you
used something like a cannonball, but still you do not get
ideal motion because it assumes are you in a vacuum.

Oh ... and that flagpole you hit on the way down really changes
your motion ... along with the parachute you are probably wearing
too. ;-)

Answer 4

They would constantly keep a forward motion (if resistance is low). The trajectory would be a superposition of the forward motion and the downward acceleration due to gravity, which forms a parabola.

Answer 5

Their fall would ideally describe an inverted parabola.

However, forward drag from the atmosphere on earth would effectively put the brakes on forward motion so that the fall, if long enough, would eventually be straight down.

Answer 6

If you were plugged in to a genius, you would know that by the law of inertia an object in motion will remain in motion with the same speed unless un unbalanced force applied to it.

Answer 7

Gravity only works in one direction, which by convention we call "down". It can only affect your up and down velocity by changing an up velocity to a down and a down velocity into a really fast down velocity.

Sideways, it has no effect at all.

If you jump off of something really high with a sideways velocity of 10 feet per second, you will hit the ground with a sideways velocity of 10 feet per second.

However, the farther you fall, the greater your down velocity will be, up to terminal velocity (the maximum speed that you can fall due to air resistance). Mythbusters are always quoting a terminal velocity of about 160 mph, which works out to about 230 feet per second.

As you go faster down, your down velocity becomes very large compared to your sideways velocity, and as a result it can seem that you are going straight down even when you are not.