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Another physics problem
I'm bored so will put forward this one to see what happens:
2 cars of equal mass crash head on at 50 mph. Both drivers will feel an impact equal to crashing into a solid object at: a. 100 mph b. 50 mph c. Other Harry K |
c
"Harry K" wrote in message om... I'm bored so will put forward this one to see what happens: 2 cars of equal mass crash head on at 50 mph. Both drivers will feel an impact equal to crashing into a solid object at: a. 100 mph b. 50 mph c. Other Harry K |
The answer is "A". 100 mph, because
E1=E2 when two cars hit head on which means each car would absorb 50 kmh of kinetic energy BUT when a car hits a wall E1 is divided in 1/2, 1/2 going to the wall and 1/2 to the car. It's all in the wording of the question. "Harry K" wrote in message om... I'm bored so will put forward this one to see what happens: 2 cars of equal mass crash head on at 50 mph. Both drivers will feel an impact equal to crashing into a solid object at: a. 100 mph b. 50 mph c. Other Harry K |
On Thu, 25 Nov 2004 11:14:19 -0500, "HotRod"
wrote: The answer is "A". 100 mph, because E1=E2 when two cars hit head on which means each car would absorb 50 kmh of kinetic energy BUT when a car hits a wall E1 is divided in 1/2, 1/2 going to the wall and 1/2 to the car. It's all in the wording of the question. "Harry K" wrote in message . com... I'm bored so will put forward this one to see what happens: 2 cars of equal mass crash head on at 50 mph. Both drivers will feel an impact equal to crashing into a solid object at: a. 100 mph b. 50 mph c. Other Harry K D. Who gives a flying **** .......LOL |
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Let's see...
The driver in the car is going 50 miles per hour, hits the "other car", then suddenly stops going 50 miles per hour. The driver in the car is going 50 miles per hour, hits the "solid object", then suddenly stops going 50 miles per hour. In both cases, the driver is slammed into the seatbelt/airbag/dashboard at 50 miles per hour. Answer b! "Harry K" wrote in message I'm bored so will put forward this one to see what happens: 2 cars of equal mass crash head on at 50 mph. Both drivers will feel an impact equal to crashing into a solid object at: a. 100 mph b. 50 mph c. Other Harry K |
By the way, were the drivers OK after this crash? I hope they were wearing
their seatbelts... |
wrote in message ... On 25 Nov 2004 08:00:27 -0800, (Harry K) wrote: I'm bored so will put forward this one to see what happens: 2 cars of equal mass crash head on at 50 mph. Both drivers will feel an impact equal to crashing into a solid object at: a. 100 mph b. 50 mph c. Other Harry K 50mph because ........................................... 2 cars of equal mass that crash head on at 50 mph can also be looked at as one car going 100mph crashing into a stationary car of the same mass. When that happens the force of the collision at 100mph is cut in two and split equally between two cars. because of the theory of relativity, the colision will be slightly less than 100 mph. randy |
wrote in message ... On 25 Nov 2004 08:00:27 -0800, (Harry K) wrote: I'm bored so will put forward this one to see what happens: 2 cars of equal mass crash head on at 50 mph. Both drivers will feel an impact equal to crashing into a solid object at: a. 100 mph b. 50 mph c. Other Harry K 50mph because ........................................... 2 cars of equal mass that crash head on at 50 mph can also be looked at as one car going 100mph crashing into a stationary car of the same mass. When that happens the force of the collision at 100mph is cut in two and split equally between two cars. ps, if you hit a wall at 100mph, the wall absorbs some shock. but the effect is the same. randy |
Harry K wrote:
I'm bored so will put forward this one to see what happens: 2 cars of equal mass crash head on at 50 mph. Both drivers will feel an impact equal to crashing into a solid object at: a. 100 mph b. 50 mph c. Other Harry K B. yawn Bob |
another answer, neither driver will feel a thing...
randy "Harry K" wrote in message om... I'm bored so will put forward this one to see what happens: 2 cars of equal mass crash head on at 50 mph. Both drivers will feel an impact equal to crashing into a solid object at: a. 100 mph b. 50 mph c. Other Harry K |
Harry K wrote:
I'm bored so will put forward this one to see what happens: 2 cars of equal mass crash head on at 50 mph. Both drivers will feel an impact equal to crashing into a solid object at: a. 100 mph b. 50 mph c. Other Harry K The correct answer is C and B If both cars, and drivers were mirror images of each other and hit perfectly head on, it will be B, but since it is highly unlikely they will be perfectly matched, it will be C as the force will be slight unequal as some parts will not collide etc. But it will be close to B. -- Joseph E. Meehan 26 + 6 = 1 It's Irish Math |
You *are* bored.
I'm bored so will put forward this one to see what happens: 2 cars of equal mass crash head on at 50 mph. Both drivers will feel an impact equal to crashing into a solid object at: a. 100 mph b. 50 mph c. Other Hmmm...is this a trick question? It's been a while.... Look at billard balls. When the cue ball strikes a stationary ball head-on (ignoring spin), the stationary ball beings moving and the cue ball stops dead. Let's say the cue ball was travelling at 50mph. Effectively it has hit a 'brick wall' at 50mph since it stopped dead. So if the second ball was travelling in the opposite direction at the same speed, the cue ball would not just stop, but 'bounce' and travel at 50mph in the oppposite direction. Effectively hitting a wall at 100mph. Correct so far? Maybe, maybe not. At this point I don't care. :) Now, that's all well and good but cars are a different story. Collisions are not perfectly elastic due to crumple zones and other losses. Assuming both cars 'stick' together after the collision, the wreck will remain stationary at the point of impact. In this case, each driver will feel the effect of hitting a wall at 50mph (i.e. each goes from 50mph to 0mph). If the cars 'bounce' off each other, then the impact will be somewhere between 50 and 100mph. Of course, dont forget about seat belts and air bags which may save their lives....if that gas leak didn't engulf the vehicles in flames first. Do you actually have an answer to this 'problem'? |
Borrall Wonnell wrote:
You *are* bored. I'm bored so will put forward this one to see what happens: 2 cars of equal mass crash head on at 50 mph. Both drivers will feel an impact equal to crashing into a solid object at: a. 100 mph b. 50 mph c. Other Hmmm...is this a trick question? It's been a while.... Look at billard balls. When the cue ball strikes a stationary ball head-on (ignoring spin), the stationary ball beings moving and the cue ball stops dead. Let's say the cue ball was travelling at 50mph. Effectively it has hit a 'brick wall' at 50mph since it stopped dead. Not really. The "brick wall" or more correctly an immovable object does not absorb any of the energy, it moves not at all. The stationary ball absorbs all the forward energy (ignoring losses) and uses this energy to move with. If the cue ball hits an immovable object it must absorb the energy itself, either bouncing off or flexing or breaking up. So if the second ball was travelling in the opposite direction at the same speed, the cue ball would not just stop, but 'bounce' and travel at 50mph in the oppposite direction. Effectively hitting a wall at 100mph. Correct so far? Maybe, maybe not. At this point I don't care. :) Now, that's all well and good but cars are a different story. Collisions are not perfectly elastic due to crumple zones and other losses. Assuming both cars 'stick' together after the collision, the wreck will remain stationary at the point of impact. In this case, each driver will feel the effect of hitting a wall at 50mph (i.e. each goes from 50mph to 0mph). If the cars 'bounce' off each other, then the impact will be somewhere between 50 and 100mph. Of course, dont forget about seat belts and air bags which may save their lives....if that gas leak didn't engulf the vehicles in flames first. Do you actually have an answer to this 'problem'? -- Joseph E. Meehan 26 + 6 = 1 It's Irish Math |
Damn, and I just packed up my old college physic books for storage until my
office gets renovation completed! I would have loved to look that one up, I can not remember most of my physics stuff, too long ago. MC "Joseph Meehan" wrote in message ... Borrall Wonnell wrote: You *are* bored. I'm bored so will put forward this one to see what happens: 2 cars of equal mass crash head on at 50 mph. Both drivers will feel an impact equal to crashing into a solid object at: a. 100 mph b. 50 mph c. Other Hmmm...is this a trick question? It's been a while.... Look at billard balls. When the cue ball strikes a stationary ball head-on (ignoring spin), the stationary ball beings moving and the cue ball stops dead. Let's say the cue ball was travelling at 50mph. Effectively it has hit a 'brick wall' at 50mph since it stopped dead. Not really. The "brick wall" or more correctly an immovable object does not absorb any of the energy, it moves not at all. The stationary ball absorbs all the forward energy (ignoring losses) and uses this energy to move with. If the cue ball hits an immovable object it must absorb the energy itself, either bouncing off or flexing or breaking up. So if the second ball was travelling in the opposite direction at the same speed, the cue ball would not just stop, but 'bounce' and travel at 50mph in the oppposite direction. Effectively hitting a wall at 100mph. Correct so far? Maybe, maybe not. At this point I don't care. :) Now, that's all well and good but cars are a different story. Collisions are not perfectly elastic due to crumple zones and other losses. Assuming both cars 'stick' together after the collision, the wreck will remain stationary at the point of impact. In this case, each driver will feel the effect of hitting a wall at 50mph (i.e. each goes from 50mph to 0mph). If the cars 'bounce' off each other, then the impact will be somewhere between 50 and 100mph. Of course, dont forget about seat belts and air bags which may save their lives....if that gas leak didn't engulf the vehicles in flames first. Do you actually have an answer to this 'problem'? -- Joseph E. Meehan 26 + 6 = 1 It's Irish Math |
C Both cars absorb impact. And at less than 50mph in concrete,
the cars crunch-absorb the energy, concrete will not . each car is like an acordion, compressing, slowing impact and force as they de-acelerate. |
C but there is velocity of the second car.. so plus 50+ ?
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Most of this energy is consumed in wadding up metal. That is the current design
criteria. |
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On 25 Nov 2004 08:00:27 -0800, (Harry K) wrote: I'm bored so will put forward this one to see what happens: 2 cars of equal mass crash head on at 50 mph. Both drivers will feel an impact equal to crashing into a solid object at: a. 100 mph b. 50 mph c. Other Harry K I suggest you consult this site: http://britneyspears.ac/lasers.htm |
"xrongor" wrote in message ...
"xrongor" wrote in message ... "Harry K" wrote in message om... (Borrall Wonnell) wrote in message . com... You *are* bored. I'm bored so will put forward this one to see what happens: 2 cars of equal mass crash head on at 50 mph. Both drivers will feel an impact equal to crashing into a solid object at: a. 100 mph b. 50 mph c. Other Hmmm...is this a trick question? It's been a while.... Look at billard balls. When the cue ball strikes a stationary ball head-on (ignoring spin), the stationary ball beings moving and the cue ball stops dead. Let's say the cue ball was travelling at 50mph. Effectively it has hit a 'brick wall' at 50mph since it stopped dead. So if the second ball was travelling in the opposite direction at the same speed, the cue ball would not just stop, but 'bounce' and travel at 50mph in the oppposite direction. Effectively hitting a wall at 100mph. Correct so far? Maybe, maybe not. At this point I don't care. :) Now, that's all well and good but cars are a different story. Collisions are not perfectly elastic due to crumple zones and other losses. Assuming both cars 'stick' together after the collision, the wreck will remain stationary at the point of impact. In this case, each driver will feel the effect of hitting a wall at 50mph (i.e. each goes from 50mph to 0mph). If the cars 'bounce' off each other, then the impact will be somewhere between 50 and 100mph. Of course, dont forget about seat belts and air bags which may save their lives....if that gas leak didn't engulf the vehicles in flames first. Do you actually have an answer to this 'problem'? Yes, it is 50mph give or take allowing for crumple zones etc. I first saw this on in sophmore physics class in HS back in 1951. Quite a discussion and got into involved math etc but it all comes down to a simple mind excercise. From what speed did each driver stop?? 50mph. so the impact is the same whether you hit a wall, a 50mph car, or a 100000mph car. i dont buy it. randy although i may be overthinking it. seems inertia comes into play somewhere.. Yes it does but each vehicle has an inertia of mass times speed (1 car x 50mph for simplicity). The inertia is expended during the crash and each one expends its own inertia, i.e., 1 car x 50 mph, resulting in 0 mph and 0 inertia. Harry K |
"xrongor" wrote in message ...
"Harry K" wrote in message om... (Borrall Wonnell) wrote in message . com... You *are* bored. I'm bored so will put forward this one to see what happens: 2 cars of equal mass crash head on at 50 mph. Both drivers will feel an impact equal to crashing into a solid object at: a. 100 mph b. 50 mph c. Other Hmmm...is this a trick question? It's been a while.... Look at billard balls. When the cue ball strikes a stationary ball head-on (ignoring spin), the stationary ball beings moving and the cue ball stops dead. Let's say the cue ball was travelling at 50mph. Effectively it has hit a 'brick wall' at 50mph since it stopped dead. So if the second ball was travelling in the opposite direction at the same speed, the cue ball would not just stop, but 'bounce' and travel at 50mph in the oppposite direction. Effectively hitting a wall at 100mph. Correct so far? Maybe, maybe not. At this point I don't care. :) Now, that's all well and good but cars are a different story. Collisions are not perfectly elastic due to crumple zones and other losses. Assuming both cars 'stick' together after the collision, the wreck will remain stationary at the point of impact. In this case, each driver will feel the effect of hitting a wall at 50mph (i.e. each goes from 50mph to 0mph). If the cars 'bounce' off each other, then the impact will be somewhere between 50 and 100mph. Of course, dont forget about seat belts and air bags which may save their lives....if that gas leak didn't engulf the vehicles in flames first. Do you actually have an answer to this 'problem'? Yes, it is 50mph give or take allowing for crumple zones etc. I first saw this on in sophmore physics class in HS back in 1951. Quite a discussion and got into involved math etc but it all comes down to a simple mind excercise. From what speed did each driver stop?? 50mph. so the impact is the same whether you hit a wall, a 50mph car, or a 100000mph car. i dont buy it. randy Almost right but not if you are doing 50mph and the other car is doing 100000 mph. in that case you would experience an impact of almost infinity. The problem is stated cars of equal mass at equal speed. It is a common belief that the speeds add, i.e, the impact would be 100 mph, they don't. Harry K |
"Harry K" wrote in message om... "xrongor" wrote in message ... "xrongor" wrote in message ... "Harry K" wrote in message om... (Borrall Wonnell) wrote in message . com... You *are* bored. I'm bored so will put forward this one to see what happens: 2 cars of equal mass crash head on at 50 mph. Both drivers will feel an impact equal to crashing into a solid object at: a. 100 mph b. 50 mph c. Other Hmmm...is this a trick question? It's been a while.... Look at billard balls. When the cue ball strikes a stationary ball head-on (ignoring spin), the stationary ball beings moving and the cue ball stops dead. Let's say the cue ball was travelling at 50mph. Effectively it has hit a 'brick wall' at 50mph since it stopped dead. So if the second ball was travelling in the opposite direction at the same speed, the cue ball would not just stop, but 'bounce' and travel at 50mph in the oppposite direction. Effectively hitting a wall at 100mph. Correct so far? Maybe, maybe not. At this point I don't care. :) Now, that's all well and good but cars are a different story. Collisions are not perfectly elastic due to crumple zones and other losses. Assuming both cars 'stick' together after the collision, the wreck will remain stationary at the point of impact. In this case, each driver will feel the effect of hitting a wall at 50mph (i.e. each goes from 50mph to 0mph). If the cars 'bounce' off each other, then the impact will be somewhere between 50 and 100mph. Of course, dont forget about seat belts and air bags which may save their lives....if that gas leak didn't engulf the vehicles in flames first. Do you actually have an answer to this 'problem'? Yes, it is 50mph give or take allowing for crumple zones etc. I first saw this on in sophmore physics class in HS back in 1951. Quite a discussion and got into involved math etc but it all comes down to a simple mind excercise. From what speed did each driver stop?? 50mph. so the impact is the same whether you hit a wall, a 50mph car, or a 100000mph car. i dont buy it. randy although i may be overthinking it. seems inertia comes into play somewhere.. Yes it does but each vehicle has an inertia of mass times speed (1 car x 50mph for simplicity). The inertia is expended during the crash and each one expends its own inertia, i.e., 1 car x 50 mph, resulting in 0 mph and 0 inertia. Harry K i pondered this for a while and the only way it makes sense to me is to assume at the point of impact you no longer have two objects, but one object with twice the mass. which is probably correct... randy |
What if they hit at an angle of 90 degrees? On 25 Nov 2004 08:00:27 -0800, (Harry K) wrote: I'm bored so will put forward this one to see what happens: 2 cars of equal mass crash head on at 50 mph. Both drivers will feel an impact equal to crashing into a solid object at: a. 100 mph b. 50 mph c. Other hence the term "head on" would not apply. Remove "YOURPANTIES" to reply MUADIB® http://www.angelfire.com/retro/sster...IN%20PAGE.html one small step for man,..... One giant leap for attorneys. |
The answer is "A". 100 mph, because
E1=E2 when two cars hit head on which means each car would absorb 50 kmh of kinetic energy BUT when a car hits a wall E1 is divided in 1/2, 1/2 going to the wall and 1/2 to the car. It's all in the wording of the question |
WHO CARES!!
"HotRod" wrote in message ... The answer is "A". 100 mph, because E1=E2 when two cars hit head on which means each car would absorb 50 kmh of kinetic energy BUT when a car hits a wall E1 is divided in 1/2, 1/2 going to the wall and 1/2 to the car. It's all in the wording of the question |
"HotRod" wrote in message ... The answer is "A". 100 mph, because E1=E2 when two cars hit head on which means each car would absorb 50 kmh of kinetic energy BUT when a car hits a wall E1 is divided in 1/2, 1/2 going to the wall and 1/2 to the car. It's all in the wording of the question i'm too lazy to search for the OP. but i have to add, are the 2 vehicles identical with 0 wind on level ground? or are you talking about 2 objects in a vacuum colliding at equal mass and velocity? did you know that a vehicle without a built in cup holder has a higher occupant survival rate than vehicles with multiple built-in cup holders? -a|ex |
"Bob" wrote in message news:ZsHqd.584312$mD.467526@attbi_s02...
WHO CARES!! "HotRod" wrote in message ... The answer is "A". 100 mph, because E1=E2 when two cars hit head on which means each car would absorb 50 kmh of kinetic energy BUT when a car hits a wall E1 is divided in 1/2, 1/2 going to the wall and 1/2 to the car. It's all in the wording of the question After all this, I certainly don't :) Harry K |
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