muck Posted January 2, 2008 Share Posted January 2, 2008 If the bullets are leaving from the same starting point and hitting the ground at the same time wouldnt they both land in the same spot ? If one also had forward movement, no. Here, try this ... shoot a rubberband and drop an identically sized rubberband from the same height at the same time. They will hit the ground at the same time. Quote Link to comment Share on other sites More sharing options...
whomper Posted January 2, 2008 Share Posted January 2, 2008 (edited) If one also had forward movement, no.Here, try this ... shoot a rubberband and drop an identically sized rubberband from the same height at the same time. They will hit the ground at the same time. This is what I dont understand. Why doesnt the dropped bullet land first since the shot bullet spends time going forward at a rapid speed ? Edited January 2, 2008 by whomper Quote Link to comment Share on other sites More sharing options...
tonorator Posted January 2, 2008 Share Posted January 2, 2008 This is what I dont understand. Why doesnt the dropped bullet land first since the shot bullet spends time going forward at a rapid speed ? i think it is because no extra time is added while the bullet moves forward. it is descending still at the rate of gravity. i conducted my own highly scientific study with a rubber band and this is apparently true. Quote Link to comment Share on other sites More sharing options...
Caveman_Nick Posted January 2, 2008 Share Posted January 2, 2008 This is what I dont understand. Why doesnt the dropped bullet land first since the shot bullet spends time going forward at a rapid speed ? Because the only applicable factor in determining how quickly the bullet travels on the "down" axis (ie, the "falling axis") is the force of gravity. The travelling at a high rate of speed is only affecting the "across" axis (ie. the "shooting direction axis"). Again, this goes back to how simple physics teaches the concepts. Az is right in saying that any difference between the time that the two hit the ground is negligible. Proving out what the difference would be is much more complicated than that difference is worth. Quote Link to comment Share on other sites More sharing options...
tonorator Posted January 2, 2008 Share Posted January 2, 2008 will a penny dropped from the empire state builidng cut through the human body if it hits someone on the head? Quote Link to comment Share on other sites More sharing options...
whomper Posted January 2, 2008 Share Posted January 2, 2008 Because the only applicable factor in determining how quickly the bullet travels on the "down" axis (ie, the "falling axis") is the force of gravity. The travelling at a high rate of speed is only affecting the "across" axis (ie. the "shooting direction axis"). Again, this goes back to how simple physics teaches the concepts. Az is right in saying that any difference between the time that the two hit the ground is negligible. Proving out what the difference would be is much more complicated than that difference is worth. OK..Thanks..Just one last point and sorry if this is redundant. The dropped bullets descent starts immediately..The shot bullets descent doesnt. If the starting point is 5 feet doesnt the shot bullet stay at 5 feet much longer then the dropped one ? I call this the "Frozen rope theory" Quote Link to comment Share on other sites More sharing options...
Tford Posted January 2, 2008 Share Posted January 2, 2008 OK..Thanks..Just one last point and sorry if this is redundant. The dropped bullets descent starts immediately..The shot bullets descent doesnt. If the starting point is 5 feet doesnt the shot bullet stay at 5 feet much longer then the dropped one ? I call this the "Frozen rope theory" This is not true. Both bullets start with 0 speed in the vertical axis. Both bullets experience force downward (gravity) in the vertical axis. Thus since the force is the same on both bullets, the acceleration must also be the same since the mass is identical. Quote Link to comment Share on other sites More sharing options...
Azazello1313 Posted January 2, 2008 Share Posted January 2, 2008 This is what I dont understand. Why doesnt the dropped bullet land first since the shot bullet spends time going forward at a rapid speed ? it moves in an arc (essentially a parabola) that is a result of two totally separate forces working on the rubber band. one force gets the thing moving horizontally at a given rate of speed. once it is moving there is no additional horizontal force, but there is also nothing (well, except for air resistance) slowing down its horizontal momentum. so it moves at a constant rate of speed (say 10 meters per second) in that direction. the second, vertical force is acceleration due to gravity. acceleration, by definition, speeds something up more the faster it is already going. gravity speeds up a falling object at roughly 9.8 meters per second, per second -- so if the object has zero downward motion at zero time, after one second it is travelling downward at 9.8 meters per second, 19.6 meters per second after two seconds, 29.4 meters per second after 3 seconds, and so on. the important thing for this particular question is that since the two forces are perpendicular to each other, there are no cancelling effects at all. the object is going to drop at a speed starting from zero and increasing at 9.8 meters per second per second whether the horizontal velocity is 10 meters per second or zero meters per second or a hundred meters per second. Quote Link to comment Share on other sites More sharing options...
isleseeya Posted January 2, 2008 Share Posted January 2, 2008 will a penny dropped from the empire state builidng cut through the human body if it hits someone on the head? no ..myth has been busted Penny Drop Adam and Jamie explore a popular claim, likely to have originated from the Empire State Building. Myth statement Status Notes A penny dropped from a skyscraper lands with enough force to either kill a pedestrian on the sidewalk below or embed itself into the sidewalk. Busted A penny's terminal velocity is too low for it to penetrate human skin - let alone penetrate concrete or asphalt - even when fired from a rifle. Quote Link to comment Share on other sites More sharing options...
AtomicCEO Posted January 3, 2008 Author Share Posted January 3, 2008 If Randy Johnson throws a baseball and I stand next to him and drop one my ball is gonna hit the ground first..Unless there is some riddlesque loophole. Not if he throws it perfectly level. If he throws it and it leaves his hand without upward momentum, and you dropped a baseball from the same height as his release point, they would hit the ground at the same time. Imagine a huge scale big enough to drive a car on. If you drove your car 100 mph on the scale, would it weight less? No. Gravity acts on it the same way regardless of it's horizontal speed. Quote Link to comment Share on other sites More sharing options...
The Irish Doggy Posted January 3, 2008 Share Posted January 3, 2008 Good Physics Info Here Quote Link to comment Share on other sites More sharing options...
wiegie Posted January 3, 2008 Share Posted January 3, 2008 What is our frame of reference concerning the measurement of time. Is it the dropped bullet or the bullet that was shot? Quote Link to comment Share on other sites More sharing options...
sundaynfl Posted January 3, 2008 Share Posted January 3, 2008 Aristotle believed that the dropped bullet would hit the ground first due to it's horizontal motion but Newton found that horizontal motion is independent of the vertical motion. If I remember the example correctly; lets say that you are traveling in a plane at 400 miles per hour and jump into the air, you will still hit the exact same spot that you jumped straight up from. The horizontal motion does not play into the vertical motion. Same thing would apply if you were driving a car down the road at 60 MPH and dropped a golf ball out of the car it would fall alongside the car just as if you were parked, so it's horizontal motion has no effect on it's vertical. Quote Link to comment Share on other sites More sharing options...
Cunning Runt Posted January 3, 2008 Share Posted January 3, 2008 Alright. I went out and shot my neighbors mule (about 500 yards) and had my granddaughter drop a bullet at the same time. Here's what happened. The loudness scared her so bad she wet her pants and forgot to drop the bullet. The mule dropped like a rock but continued to kick in nervous contractions for about 5 minutes. My son said "Dad, that was the wrong mule." We are now digging a hole to bury the dead mule before anyone notices he is missing. My son asked what the hell was this all about. Thanks. Another Huddle experiment gone wrong. Reminds me of the brake fluid/smoke bomb thing awhile back. Now that was some funny chit right there. Quote Link to comment Share on other sites More sharing options...
montster Posted January 3, 2008 Share Posted January 3, 2008 Aristotle believed that the dropped bullet would hit the ground first due to it's horizontal motion but Newton found that horizontal motion is independent of the vertical motion. If I remember the example correctly; lets say that you are traveling in a plane at 400 miles per hour and jump into the air, you will still hit the exact same spot that you jumped straight up from. The horizontal motion does not play into the vertical motion. Same thing would apply if you were driving a car down the road at 60 MPH and dropped a golf ball out of the car it would fall alongside the car just as if you were parked, so it's horizontal motion has no effect on it's vertical. this is incorrect. if you're in a plane traveling 400 mph, then you yourself are traveling 400mph. negating all other factors, when you jump out, your horizontal velocity will carry you a certain distance from where you jumped, depending on how high you were. horizontal velocity has no effect on vertical velocity; the same can't be said about their respective distances. by the logic above, if i jumped from a moving train, i would just land harmlessly on the ground, as if the train were at rest. in reality, that's not the case. Quote Link to comment Share on other sites More sharing options...
isleseeya Posted January 3, 2008 Share Posted January 3, 2008 Alright. I went out and shot my neighbors mule (about 500 yards) and had my granddaughter drop a bullet at the same time. Here's what happened. The loudness scared her so bad she wet her pants and forgot to drop the bullet. The mule dropped like a rock but continued to kick in nervous contractions for about 5 minutes. My son said "Dad, that was the wrong mule." We are now digging a hole to bury the dead mule before anyone notices he is missing. My son asked what the hell was this all about. Thanks. Another Huddle experiment gone wrong. Reminds me of the brake fluid/smoke bomb thing awhile back. That is hilarious Quote Link to comment Share on other sites More sharing options...
jackshi17 Posted January 3, 2008 Share Posted January 3, 2008 Don't forget to remove the bullet from it's casing before trying this experiment. Quote Link to comment Share on other sites More sharing options...
Azazello1313 Posted January 3, 2008 Share Posted January 3, 2008 this is incorrect. if you're in a plane traveling 400 mph, then you yourself are traveling 400mph. negating all other factors, when you jump out, your horizontal velocity will carry you a certain distance from where you jumped, depending on how high you were. horizontal velocity has no effect on vertical velocity; the same can't be said about their respective distances. by the logic above, if i jumped from a moving train, i would just land harmlessly on the ground, as if the train were at rest. in reality, that's not the case. what he is saying is that it is all relative. if you're in a plane and the plane and you inside it are both going 400 mph (relative to the surface of the earth) then relative to the plane you're not moving horizontally at all so if you jump you land in the same place on the plane, and you don't stay in the air longer because of your speed relative to the surface of the earth. that's what he meant by the horizontal being independent of the vertical. jumping from a moving train to the ground is totally different, because you are jumping from one platform to another and the platforms are moving at very different speeds relative to each other. Quote Link to comment Share on other sites More sharing options...
Pope Flick Posted January 4, 2008 Share Posted January 4, 2008 There's a 90-100 page short version of the Theory of Relativity written by Einstein. The basic concepts are easy to understand - like how sundaynfl has the whole vertical thing incorrect. But what's fasciniating about the book is that while you are reading it most of it makes sense. But once you put it down, it becomes liek last night's dream: the more nuanced parts of the theory simply evaporate as if you're a dog that's been taught to fetch with no reason why. You can pick it up again, and re-read to refresh but the tough stuff disappears once again after putting it down. Quote Link to comment Share on other sites More sharing options...
sundaynfl Posted January 4, 2008 Share Posted January 4, 2008 this is incorrect. if you're in a plane traveling 400 mph, then you yourself are traveling 400mph. negating all other factors, when you jump out, your horizontal velocity will carry you a certain distance from where you jumped, depending on how high you were. horizontal velocity has no effect on vertical velocity; the same can't be said about their respective distances. by the logic above, if i jumped from a moving train, i would just land harmlessly on the ground, as if the train were at rest. in reality, that's not the case. I never said that you would jump out of the plane.... you are jumping inside the plane. I should either slow down when typing these posts or you and Pope should slow down while reading them... Here is an article that discusses the exact same point and it seems pretty clear to me... Newtons Laws in Three Dimensions Quote Link to comment Share on other sites More sharing options...
montster Posted January 4, 2008 Share Posted January 4, 2008 what he is saying is that it is all relative. if you're in a plane and the plane and you inside it are both going 400 mph (relative to the surface of the earth) then relative to the plane you're not moving horizontally at all so if you jump you land in the same place on the plane, and you don't stay in the air longer because of your speed relative to the surface of the earth. that's what he meant by the horizontal being independent of the vertical. jumping from a moving train to the ground is totally different, because you are jumping from one platform to another and the platforms are moving at very different speeds relative to each other. I never said that you would jump out of the plane.... you are jumping inside the plane. I should either slow down when typing these posts or you and Pope should slow down while reading them... Here is an article that discusses the exact same point and it seems pretty clear to me... Newtons Laws in Three Dimensions sorry, you're right, i mis-read the post. i thought you meant if you dropped the golf ball out of the moving car, it would hit the ground as if it were parked, but i see that's not how it was written. i shall punish myself by jumping from a moving train. where will i land? Quote Link to comment Share on other sites More sharing options...
Pope Flick Posted January 4, 2008 Share Posted January 4, 2008 I never said that you would jump out of the plane.... you are jumping inside the plane. I should either slow down when typing these posts or you and Pope should slow down while reading them... Here is an article that discusses the exact same point and it seems pretty clear to me... Newtons Laws in Three Dimensions When you're talking about bullets hitting the ground(which Aristotle did NOT do), then jumping in a plane, things can get confusing. You should get the Relativity Book, it is quite the read. Quote Link to comment Share on other sites More sharing options...
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