Is it really true that the speed of an object when thrusted into the air is the same as going down to the ground.
For example, if you throw a ball in the air, is the speed of it leaving your hand the same as landing?
Also, if you shoot vertically with a gun/rifle, is the speed of the bullet leaving the gun the same when it's coming down?
(That would be really dangerous)
I'm just curious...
2006-07-12 12:08:32 · 9 answers · asked by Anonymous in Science & Mathematics ➔ Physics
ALSO, IF ANY OF YOU SAY SOMETHING ABOUT AIR RESISTANCE, WOULDN'T THERE BE AIR RESISTANCE , TOO WHEN IT GOES UP?
2006-07-12 12:18:00 · update #1
the speed of a bullet is faster than the speed of sound!
2006-07-12 12:21:24 · update #2
No.
The speed of the object going up depends on the power used to propel it - and its speed will decrease as it ascends by the force of gravity - at the rate of 32 ft/s^2. The speed of the object coming down is always the same - it starts at 0 (when the object stops ascending) and accelerates at 32 ft/s^2
[edit]
remember F=ma
then a = F/m
in this case,
a = is the acceleration that the object will experience.
F = the sum of all forces acting upon the object (on the accent, its the force used to propel it up minus the force due to gravity minus friction)
m = mass of the object.
and speaking of bullets fired in to the air: Myth Busters did a thing on this a while back and proved that a person could not be killed by a bullet, fired from a gun, falling back to earth.
[edit] In response to your "additional information"
What does the bullet traveling faster than the speed of sound have to do with anything? If you fire a bullet straight up in the air, it's *velocity* at any point time can be calculated using the the following equations:
(assuming no air resistance)
going up: (-32t + V0) ft/sec, where V0 is the muzzle (initial) velocity in feet/sec and t is time in seconds.
coming down: +32t ft/sec (comming down, V0 is 0)
2006-07-12 12:13:16 · answer #1 · answered by Will 6 · 3⤊ 0⤋
No. This is completely wrong. The velocity of anything you just thrusted vertically in the air is defined by how much a strong "kick" you gave to it. This velocity will also determine how high it will go before it will stop and start coming down.
I think you are a little bit confused with the fact that no mater how heavy something is it will fall (free fall no air resistance) always with the same acceleration. Thus if you drop from an airplane a truck and a golf ball they will both reach the earth at the same time with exactly the same speed (assuming no air resistance). The damage that the truck will make will be more due to its momentum.
some equations for you
F=mg (Force = mass * acceleration of gravity)
a = v/t (acceleartion is the rate of change of the velocity)
Terminal velocity is the minimum velocity required for a mass to escape the gravitational field of the earth. Thus if you could thrust something at that speed it will never "go down".
2006-07-12 12:31:14 · answer #2 · answered by Sporadic 3 · 0⤊ 1⤋
Coming Down From Speed
2016-12-17 16:55:17 · answer #3 · answered by Anonymous · 0⤊ 0⤋
Theoretically, in ideal conditions, yes. However, it slows a little due to drag. This has more of an impact as the surface area increases with respect to the mass (more drag).
The bullet coming down is really dangerous. That's why you're not supposed to shoot into the air at New Year's (an old custom) in urban areas. In an urban area it's sure to hit something on the ground!
2006-07-12 12:16:19 · answer #4 · answered by Alex 3 · 0⤊ 0⤋
For common situations, yes.
But consider of you threw so hard it left the planet. Then the question doesnt work. Also, when coming down, an object is going to eventually achieve terminal velocity because of air resistance. So if it left your hand faster than that, it wouldn't re-achieve that speed of launch. But normally just tossting things up, it winds up coming down the same speed.
2006-07-12 12:13:16 · answer #5 · answered by Rjmail 5 · 0⤊ 0⤋
No. Air resistance would slow both objects down on earth. You wouldn't want to get hit with a falling bullet, but its travelling far slower than when it left the barrel.
Good question.
2006-07-12 12:14:34 · answer #6 · answered by Anonymous · 0⤊ 0⤋
As long as the object doesn't go so high that on its way down it reaches its terminal velociy, yes. With a gun or rifle, they reach terminal velocity on the way down.
As far as air resistance goes, it affects it on the way down due to acceleration and terminal velocity, on the way up, it is decelerating, so terminal velocity (due to gravity) doesn't come in to play
2006-07-12 12:12:27 · answer #7 · answered by thepathfinder804 3 · 0⤊ 0⤋
excluding minute differences then yes same speed
2006-07-12 12:11:38 · answer #8 · answered by kevin h 3 · 0⤊ 0⤋
No, please look up terminal velocity on the web since i don't feel like typing.
2006-07-12 12:13:54 · answer #9 · answered by galactic_man_of_leisure 4 · 0⤊ 0⤋