why the car wheel are round?
483509
yeah, the rhombus wheels werent so great either.
1134357
because the wheels are pushing back at the ground, the ground in turn pushes the car
444984
My bottom shaped car is a work of art! Any car (be it pink with a penis shaped gearstick, or penis-shaped with a pink gearstick) would be very excited by my car. And if I really squeeze (on the brakes) it leaves skid marks....
1046019
when a car speeds by you, you feel wind. it's the same way with the earth, as it spins very fast.
28916
That's just the nature of the optics. They need to be bent in order to have you - from the front seat - see a wide enough area along the side of the car. The result is a curved lenses and distortion.
202373
Diameter? Think extremes, a 20" diameter wheel will go much further in one revolution than a 10" wheel. So with the engine doing the same speed, the car would go further in the same amount of time - faster!\n\nSo providing both wheels weighed the same, a larger diameter tyre will make the car go faster.\n\nIn practise the wheel and tyre weighs more, so the difference is hardly noticed, you can have a wheel that is too big. Someone once put 19" wheels on his big powerful car and kept snapping his driveshafts!
988792
The relative speed of the rotation of the tire to the road is not what wears a tire. It's Newton's law stating that every force has an equal and opposite force. As the tire is rotating on the car, the engine needs to produce a significant amount of torque in order to move the car. That torque is also acting on the tire as an opposite force as provided by the ground and by friction. Besides that, other factors are involved like the compression of the rubber, sideways forces from turning, and heat generated and absorbed by the road.
124798
This has to do with the way the earth was formed. Dust particles gathering together and spinning at the same time. Spinning causes things to take spherical shape due to centrifugal force.
8264
It's because of the minor imperfections in the placement of the mirrors. Also, because the effect can't be seen without seeing it at an angle, it causes a curve based on your viewpoint.
4088
because the air inside the car is moving with the car
831050
One is for making car body which can easily return to its original configuration anfter an accident. Usually heating of the body (e.g. by hot water) can cause it to gain its original shape.
77085
Because it is refracting light that is coming from all around. When you see a rainbow produced by a prism it looks straight but if you were able to enlarge it enough it would be round.
542150
Because the air and all objects inside of the car are going the same speed as the car, try driving around a corner with a helium ballon. If you take a right corner the ballon will go to the right side of the car while you go to the left side.
524282
There are two possible reasons:\n1. A non-round object has higher surface area than a round object for same volume. This in turn could lead to higher reaction rates in portions that are not round (projections etc), finally leading to the element appearing round.\n2. The surface tension of water and buoyancy keep the element on the surface at the cost of local depression in the surface of water. Surface tension tends to make the depression round, which could make the element appear round.
756380
Firstly, let me point out to you which answers are wrong and which answers are right. Otherwise you'll be just as confused as you were to begin with.\n\nThe first answer is confused. The second and third answers have no idea of what their talking about. The other answers are correct.\n\nHere's why the first answer is confused:\n\nSpeed and velocity use exactly the same units. \nSo it is perfectly acceptable to say "a car travels around a sharp curve a 60 km/hr". \n\nRestated, what we are saying is that the car moves around a curve at constant speed of 60 km/hr. The statement above does not include directional information. \n\n(However, suppose we said "a car travels around a sharp curve with constant velocity of 60 km/hr". Then, clearly this would be wrong. Velocity does change as it goes around the curve.)\n\nSecondly, let us recall some basic facts of 'Uniform Circular Motion' \nAn object that travels with Uniform Circular Motion has:\n- constant speed \n- changing velocity  \n- acceleration towards the centre\n\nNow, the car in question displays uniform circular motion. This is so even though we are considering a partial circular path.\n\nSo, we can use this import formula (you should memorise it) \n\n    ar = v ^2 /r\n\nThis relates the centripetal acceleration, ar, to the radius of the circle (or in the case of a partial circle, the radius of curvature), r.\n\nFrom the formula you can see that a sharp bend, i.e. a small r, will give a larger value of centripetal acceleration compared to a gentle bend, i.e a large r. \n\nSubstitute v=60 and different values of r into the formula above to verify this.
197291
to get the offset on the crown wheel inside the diff to turn.Thus causing the axle shaft to spin.
490009
Because the normal force of the road upon the car is not directed straight upwards, as it is on a flat road. The normal force vector is tilted inward toward the center of the radius of curvature (assuming that the road engineers built the darned thing correctly) by an amount equal to the angle of the bank of the road. Decomposing the normal force vector into a horizontal (towards the center of the circle) and a vertical (up towards the sky) shows an increased force upon the car towards the center of the radius of curvature over the case where the road is flat. In the end, it means that the coefficient of static friction that keeps the wheels from sliding radially away from the center of curvature doesn't need to be as high when the road is banked.\n\nAlso note: There is NO SUCH THING AS CENTRIFUGAL FORCE! The car is an accelerating reference frame. Anyone who uses the term "centrifugal force" either has not taken 1st year physics or did not understand it when they did.