In a driveshaft where would be high stress concentration, in a particular in yoke part. If any doudt regarding this please free to ask me again. Or please tell where can i find information.
126194
The highest "concentration" of stress will occur at "stress risers."  For example if a shaft is divided along its length with two different diameters, each half will flex depending on its diameter but at the transition there may be a sudden change in stress causing the local stress (in psi - pounds per square inch) to rise well above the average stress of either half on a microscopic basis.  This is where cracks may first form under heavyload.  A very sharp "corner" (small radius) at the change in diameter will increase stress concentration while a large rounded corner will lessen stress concentration (and stress!).  A coone-shhaped transition may be even better.  Any reduction in uniformity of the shaft cross-section (perhaps a key slot) will form a stress riser perhaps requiring the entire shaft to be larger and stronger to compensate for the key-way design.  The yoke you mention would constitute a nonuniformity and could create stress risers and stress concentration.  This is a factor to be considered in good design since it can not be eliminated but only recognized and minimized.  Curved parts are often better than parts with sharp corners or tight bends.  That is why service life tests of components and failure analysis leads to improved designs.  A better design may require a different steel alloy or larger radii when machining or grinding parts or even de-rating allowable loads.  Hope that helps a little.
183627
Yes,but it's providing downforce to stick car to track better.The car is going to cut the air,and you sure don't want it to go under,then car would lift up and get airborn.
249451
You should show how ice expands and can damage roads and concrete... very stiff materials.\nCheck out the links\n\nOh yes and don't forget about wear and tear cars and other vehicles can cause... I am not sure how much time you have for your science fair project... typical road wear studies can last for years.
664589
I was in the Air Force driving 1000 miles to go home for a month leave. While I was driving in the high mountains around Reno, I fell asleep. I was traveling about 85 mph. My truck veered off the highway. As soon as I felt the truck leave the highway, I woke up and found I was heading downward on the gravel part of the side of the highway. My truck seemed to be driving itself I was in shock. The steering wheel was moving under my hands. I can't describe it any better than this. As the truck moved back up to the highway, I pulled over and tried to calm down. It was a really frightening moment. What was even more frightening was just 1/4 mile more and the side of the highway no longer had gravel. There were large boulders. I still get chills thinking about it.\n\nTill the day I die, I know I was not the one driving my truck at that moment.\n\nbtw - I have had several other experiences where the circumstances involved other than human interaction. I guess I am just one of the few to have been fortunate enough to experience it.
315214
Try just driving around quiet streets, if there are any in your area, but if that's not an option, can you go to a not very busy car park? That's what I did, it boosted my confidence quite a bit. The more you drive, the better you'll become, and bear in mind it was a 'near' accident, you obviously have good driving skills as you avoided a collision. Well done, keep it up young man!
425169
I always check both the mirror and with a head check (my father and grandfather have both been truck drivers in the past, and so with their commercial licenses and good driving records they gave me lots of advice). However, my driver's ed instructor actually berated me for this habit. He said it was dangerous to take your eyes off the road in front of you for even the brief second of time required to do a head check. Which is totally ludicrous, since if you stared straight out the windshield the whole time you were driving you'd never be able to read the speedometer or check any of the gages. Needless to say, as soon as I was out of his class, I completely ditched his driving advice. And as a further note, he was later fired from another school after he drove his vehicle into one of the school's buildings. Safe driving techniques, anyone? Unfortunately, I believe many driver's ed instructors may be advising against the head check, too, though, which I think is a sham. However, if you take an accredited motorcycle safety course, they'll definitely recommend the headcheck regardless of the type of vehicle you're controlling at the time. =)
638517
Hey there:\n\nInteresting question, because a month ago, i stumbled upon a thrown away harddrive while walking my dog.  I desembled it while I was at home, and found inside it TWO EXTREMELY POWERFULL RARE EARTH MAGNETS.  Also, around on each side of these magnets, was a magnetic shield, that did not allow them to attract from one side, but yes from the other.  If I was you, look for any thrown away harddrive, they all have them, and you will also be getting an extremly powerfull magnet while you are at it.
184132
HAHAHAHA You all forgot about our little friend called drag! Inside or out the ball has a drag force acting on it by the surrounding air. Like stated before the air in the car is moving with you, and the car, and the ball all the same and the drag force on the ball at this point is negligible. This is not the effect of a vacume, a vacume is the absence of air. is it possible for there to be no air in the car? NO, Sooo.. outside on a bike or where ever, you are traveling at a speed where the balls light weight will be significantly affected by this drag force and it will cause it to slow down as you throw it up and while you keep riding on un affected by the static(motionless) air, your ball only has one force acting on it, air drag causing it to slow behind you.   test this by throwing a variety of same shaped objects while riding and you will see that the one with the most density will keep up the best. try a marble V.S. a ping pong ball.  then do it in the car
187029
Shifting without letting off of the gas!  Keep your right foot matted to the floor and just brush the clutch pedal--snatch a gear and keep gittin' up!
674957
No damage, it warms them a bit (but not much).  Curiously I have wondered what happens if they spin tyres going over a wheel nut that has been removed.\n\nI raced for a few years here in England and here we have standing race starts, not rolling starts as in NASCAR.  Believe me in a race start situation the slightest wheel spin and you are engulfed by the field behind.  You learn not to spin the tyres, believe me.
20315
One of the classic inefficiencies of cars of yore is the driveline design.  Take for instance a 1962 V-8 Impala with a hydramatic transmission and rear wheel drive.  The two-speed transmission always allowed slippage between the engine and the wheels, which caused energy loss in the transmission fluid being heated up in the torque converter during all driving situations.  They have cured that in today's automobiles by locking out the torque converter with an automatic clutch.  Putting a 90 degree angle between the input and output is also an energy sucker.  In more efficient front wheel drive cars, the axis of engine revolution is the same as the wheels.  This saves some energy as well. The final drive ratios of cars in the 60's was insane!  A cruising RPM of 3600 at highway speeds was not unheard of--and on a V8!!! Think of the gas going down the tubes.....  Modern cars reduce the final drive ratio and add overdrive to the transmission to reduce cruising speed RPM.  Less RPM means less air consumption and less fuel use.  In the 70's, they caught on and offered rear wheel drive cars with 2.73:1 rear end ratios to save gas.  This hurt acceleration, but was cheaper than offering a 4 speed automatic.  (It eventually happened.)  \n\nA huge determinant of efficiency is COMPRESSION RATIO.  Without computer control and injection, most cars of the 70's (BAD efficiency) had LOW compression ratios, say 8.0.  (And food for thought--the first spark ignition engines had a sorry compression ratio of 4.0:1.  How sad!!  They did not know enough about fuel chemistry at the turn of the century, so that's why the horsepower value of vehicles was so low back in the teens. A four cylinder automotive engine having 10hp in the "old days" with a displacement of 2 liters.  WOW!) New cars have all kinds of tricks to increase compression ratios while running on regular 87 octane fuel.  Current compression ratios include 9.0 to 10.1.  Computers adjust injection and spark ignition timing (to repeat a collegue's information already submitted) along with monitoring piezoelectrick "knock" sensors which make adjustments for preignition "pinging."  In the old carbureted cars, even ones with HEI ignition, there was no way to deal with the pinging. The sure fire way to prevent pinging (and serious damage) is to lower the compression ratio.\n\nAnother huge problem with cars of the 70's and 80's were the addition of the catalytic converter and other emission control systems like the huge drain from a "smog pump."  EGR valves put exhaust in the intake charge to reduce nitrous oxides, but that reduces peak combustion temperatures and the available power from the fuel charge.  Running exhaust through the manifold also made the intake charge hotter, reducing efficiency.  Old cars had fixed valve timing, which determines the relationship between power at high rpm and torque at low rpm.  Some manufactures today have adjustment on the exhaust valve timing, and some even adjust both the exhaust and the intake timing to increase efficiency and torque at low RPM while changing valve overlap for high rpm horsepower with a net smaller displacement.\n\nSome modern cars still include EGR, but the catalytic converter technology is much better and more attention to exhaust system design has helped increase MPG.\n\nThe actual energy used by the valvetrain has also been reduced by reducing the mass of the components in the valve train.  Using a cog belt to a cam riding right above the valves reduces the energy used to activate the valves.  That can really add up over the life of the engine.  \n\nAnother development was the inclusion of the electric cooling fan.  Belt driven fans consumed huge amounts of power from the engine, even if they had a thermal clutch.  Flex fans were supposed to reduce energy, but we are still talkin' in the multi-horsepower range just to move air across the radiator.  The modern c
78674
When you burn avalv or warp a head and blowe a gasket you need a head job.Look up engin repear.
642744
Here goes nuttin'.... Trust me on this, I used to design and produce asphalt. Air voids in the asphalt are the most likely cause. Asphalt is designed with a certain percentage of air voids to help it shed water and to allow for expansion and contraction of the asphalt due to temperature changes. As the water seeps into these voids, air escapes. totalabyss, I agree with you. As far as oil being used while everyone else can't spill oil all over. Asphalt Cement, and automotive oils differ in many, many ways. You cannot pour asphalt out of a container at ambient temps. If it were a liquid @ 90 degrees, what would the road you drive on look like? The oil you spill all over actually hurts the roads us taxpayers pay for, plus it gets into the water system. If you ever come across an old chunk of asphalt, try this. Pour some hydraulic fluid or diesel on it, it will turn to mush. So, if this were to happen, say on one sq. ft. of road on every block in your neighborhood, the city would have to cut out the area, and replace it before it eats into the ground. So now this $3 used oil on our road is now costing us taxpayers $1800 to repair.
652903
A long skinny cylinder is the preferred shape for high pressures.  But if you have a cylinder and a sphere with the same diameter and wall thickness, the sphere will have a slightly smaller hoop stress because theoretically there is no "hoop" in a sphere since the diameter is never a constant over any width of cross section.
564250
Drive more often. Work on your jumper... Drive more often.
402821
Look at flexions at the point of supprt:\n1 is the support solid so its flexure can be ignored\n2 is the steel rod held by a grub screw. If it extends any distance to lock the rod then some rotation will occur due to it bending\n3 if held in a chuck check slippage.\n\nIn motor cars torque transmission is usually accomplished using splined shafts, but for small oscillations the backlish in these will be large.
68016
They WILL affect your car..that is, if you manage to fit 285/50 x 20" on a merc E. The ABS will not engage properly, nor will the traction control, if u have any. U'll burn away the clutch faster as u start-off, u'll wear-off the brakes in no time as u try to stop the 20s from spinning. There's also the added weight. More than that, since all mercs are RWD, u should think about fitting different tires with different widths for the front and rear axles (ie wider at the rear axle). Good Luck anyways!