My friend says since objects fall to the ground at 9.8 meters per second, that if you fired a gun into the air completely parallel to the ground at a height of 9.8 meters, than the bullet would take 1 second to reach the ground after it was fired. I think the force on the bullet to move forward would counter-act the force of gravity for a while, causing the bullet to stay in the air for longer than a second. What is the correct theory???
2007-04-20 11:36:01 · 13 answers · asked by Milo 1 in Science & Mathematics ➔ Physics
It will take more than 1 second, but for a completely different reason than you think, so it depends on how the bet was worded as to who, if anyone, won. From a knowledge of physics standpoint, however, you're both wrong.
"The force on the bullet to move forward" is orthogonal to the force (gravity) causing the bullet to fall, so the resultant accelerations are orthogonal too and, therefore, do not effect each other. However, the *acceleration* due to gravity g is 9.8 meters per second per second. The time it would take to hit the (horizontal) ground from a height h of 9.8 m is therefore t=sqrt(2x/a) = sqrt(2) sec = 1.414 seconds.
2007-04-20 11:47:30 · answer #1 · answered by Dr. R 7 · 2⤊ 0⤋
Projectiles have two components to their velocity: horizontal and vertical, and they are completely independent of each other. This means that a bullet fired at any speed horizontally will hit the ground in exactly the same time as a bullet that is simply dropped from the same height (ignoring wind, air resistance, and the curvature of the earth).
When anything falls near the surface of the earth, its downward velocity starts at zero and accelerates to the tune of 9.8 meters per second *per second*. In other words, after one second the object will have an *velocity* of 9.8 m/s, but it will only have fallen 4.9 meters in that time, from the distance formula s = 1/2 g t^2. After 2 seconds it will fall 4.9 * 4 = 19.6 meters, after 3 seconds 4.9 * 9 = 44.1 meters, and so on.
The acceleration is a constant 9.8 m/s/s and the velocity keeps increasing until it hits the ground.
2007-04-20 13:07:17 · answer #2 · answered by hznfrst 6 · 0⤊ 0⤋
Your friend is correct. All things experience an acceleration of about 9.8 m/ sec^2 towards the earth. If the bullet has no vertical component to it's velocity, then it will hit the ground after one second if fired from a height of 9.8 meters. A bullet dropped from your hand from the same height would also hit the ground at the same time as the fired bullet. Many, many tests have been done to prove this fact.
2007-04-20 11:46:07 · answer #3 · answered by Kender_fury 3 · 2⤊ 2⤋
Air resistance will only make the bullet fly less, horizontally. The vertical forces are the same regardless of how fast or slow the bullet is going.
The exact formula to calculate the time is:
x = x0 + v0*t + 1/2*a*t^2
x is 0 (ground level)
x0 is 9.8 meters
v0 is 0 (no initial vertical velocity -- gun is pointed horiz.)
a is -9.8 meters/second^2 --- note it is: per second squared
0 = 9.8 + 0 + 0.5 * -9.8 * t^2
solve for t: 1.414 seconds.
.
2007-04-20 11:49:43 · answer #4 · answered by tlbs101 7 · 0⤊ 0⤋
You friend is correct. Motion in the horizontal and vertical directions are independent of each other. If you stand still and fire a bullet parallel to the earth and drop a bullet from your hand, they will both reach the ground at the same time.
2007-04-20 11:47:31 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Your friend is correct. While a faster bullet will cover more ground before it hits the ground, the it will still hit the ground at the same time as a slower bullet. Keep in mind that distance and time are not the same thing.
2007-04-20 11:46:40 · answer #6 · answered by Anonymous · 2⤊ 0⤋
In absence of air resistance the bullet will hit
the ground in time √(2h/g) = 0.45 second.
Because of air resistance, it may take longer
than a second. Earth curvature is insignificant
as actual bullet speeds (300 to 800 meters per second)
are much smaller than orbital speeds (8000 meters per second).
2007-04-20 11:51:06 · answer #7 · answered by Alexander 6 · 0⤊ 1⤋
if guns no longer shot bullets, then why would we have guns? melt em down! if guns fired second chances, yes i would be like cupid and shoot straight for the heart, the heart is the organ that is the most hurt, needs the second chance to heal and be complete!♥
2016-05-19 23:30:32 · answer #8 · answered by myung 3 · 0⤊ 0⤋
Unless that bullet goes far enough for the curvature of the Earth to affect it, it's going to hit the ground in the same time as if you dropped it.
2007-04-20 11:40:31 · answer #9 · answered by Nomadd 7 · 3⤊ 1⤋
need to qualify that answer, todays ammunition, you can google the bullet trajectories, realize that charge/burn rate slug weight all enter into this equation. my .223 AR-15 at 1 mile has a almost flat trajectory, my AK47 (30 calib) has abt a 5" drop at 1 mile. as for nukes, you can't outrun em! the answer to your basic question is: yes my 30 cal M1 carbine, less powder 95gr bullet weight/ at 1 mile larger drop. all these things are design factors...engineering, not magic
2007-04-20 11:58:26 · answer #10 · answered by Anonymous · 0⤊ 1⤋