A Dumb Question About Trajectory
- Thread starter Industrial Toys
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You are right. But time of fall does matter, and velocity changes time. A bullet that takes 1/4 second to go 100 yards will fall more than one that takes 1/8 second.
Bruce
KennyG
Elite Member
Correct. The easiest way to think of this is the horizontal and vertical motions can be considered independently. In a level shot, the bullet will leave with a certain velocity and slow (decelerate) gradually as drag slows it in the horizontal direction. At the same time it will drop due to gravity, accelerating under gravity (with a slight drag force reducing the acceleration). It will reach the ground in the same time it would take if you just dropped it. The total distance it travels depends on the muzzle velocity.
If you aim it up or down, the acceleration of gravity adds to the initial vertical velocity (up or down). (That will be the muzzle velocity times the sine of the angle of the shot). Aiming it up or down changes the time it takes to fall to earth via gravity and, as a result, the total horizontal distance covered.
/pine
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Yes and the only other factor would be the displacement...where the curvature of the Earth enters the equation...
GPintheMitten
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No bullet goes flat. The shape of bullet travel is a parabola.
davesl708
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That is correct. When you plot the curve on an object dropped straight down you get a vertical line. When you move the object forward on a horizontal line the curve forms. The farther the object moves on the horizontal the smoother the curve. The slower it moves the steeper the curve. The time/distance in the air spreads out the curve.
OP
Industrial Toys
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The projectile rotates for stability. Would this not counteract or resist gravity to a very small degree as well?
davesl708
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The rotation will help keep the projectile on its intended path but not keep it in the air longer. Spin comes in to play in long distances (1500yds) due to spin drift causing the projectile to move to the side.
2LaneCruzer
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I have always thought of it like this: The trajectory of a bullet sighted in at say 50 yards will have a trajectory like a rainbow (slight exaggeration). Depending on how the gun is sighted in, the bullet will be dead on the line of sight at say 50 yards and again about 100 yards. Because of the rainbow effect, caused by gravity and the fact that the aim is ever so slightly at an upward angle, the trajectory will place the bullet below the aiming point at a distance below 50 yards, above the aiming point beyond 50 but less than 100; right on at 100 and below beyond 100.
If you are shooting straight up or straight down, the effect of gravity on the trajectory is minimal, ergo the bullet will be high at the point of aim (since there is no compensation for gravity), therefore aim a little low...
If you are shooting straight up or straight down, the effect of gravity on the trajectory is minimal, ergo the bullet will be high at the point of aim (since there is no compensation for gravity), therefore aim a little low...
