When viewing cars that are driving along side of us, sometimes their wheels appear to be turning backwards even though they are traveling in the same direction as our car. Why do they look that way?
Rotational Dynamics – Why Do Wheels Appear to Revolve Opposite to Their Rotation Direction?
everyday-liferotational-dynamics
Related Solutions
The stripes appear to move faster in Case B because of the angular velocity that they have. In a reference frame centered on the observer, the velocity stripes in Case A is mainly directed radially, which means they do not have much angular displacement (the direction in which one looks in order to observe them doesn't change much). This allows the eye to easily track the stripes and it gives one the time needed to properly resolve the stripes and their size/shape. However, in Case B, the velocity is mostly tangential to the observer, which means that most of the displacement is angular and not radial (the direction you have to look at in order to track a single stripe quickly changes). This requires one's eyes to move quickly in order to follow a single stripe. The rapid motion across the eyes' field of view is interpreted in the brain as faster motion. Faster angular velocities means it's harder for your eyes to move and properly focus on a single stripe, which makes them look more blurred. At a certain angular speed (I don't know the limit as I'm a physicist, not a biologist), the eye can no longer move fast enough to track a single stripe and so it simply sits and watches the stripes zoom by in a blur.
This is all a matter of how fast the eye has to move to follow the object. Far ahead, the eye barely has to move at all and so it can see and follow the object easily. Adjacent objects cover a larger swath of one's field of view, so the eye must move much faster to follow them. That's about it
Because friction is your method of steering! (- and of braking and accelerating.) As @MasonWheeler comments:
This is such an important principle that there's a special name for it: in the specific context of using applied friction to direct motion, friction is also known as traction.
Turning / steering
Friction is what makes you turn left at a corner: you turn the wheels which directs the friction the correct way. In fact, by turning your wheels you turn the direction of friction so that it has a sideways component. Friction then pushes your wheels gradually sideways and this results in the whole car turning.
Without friction you are unable to do this steering. No matter how you turn your wheels, no force will appear to push you sideways and cause a turn. Without friction the car is drifting randomly according to how the surface tilts, regardless of what you do and how the wheels are turned.
Braking and accelerating
Accelerating and braking (negative acceleration) requires something to push forward from or something to hold on to. That something is the road. And friction is the push and the pull. No friction means no pull or push, and braking and accelerating becomes impossible.
So, friction is very, very important in any kind of controlled motion of vehicles that are in touch with the ground. Even when ice skating, you'd have no chance if the ice was 100% smooth.
It should now be easy to grasp that it's a problem to go from static friction (no slipping of the tires) to kinetic friction (the tires slip and skid), simply because kinetic friction is lower than maximum static friction.
If you brake e.g., it is better to have static friction, because it can reach higher values than kinetic friction and thus it can stop you more effectively.
Best Answer
The issue appears to be rather complex, so I do not aim at providing an exhaustive answer.
At a toy model level it is reasonable to model the eye as a "camera". Specifically, let us assume that a human eye "samples" at a maximum frequency of $\nu$, so that we may make use of the Nyquist-Shannon sampling theorem. Basically, given an instantaneous angular velocity of $\omega$, if the wheel has $n$ spacings, then the "highest frequency" component is $n\omega\over{2\pi}$ (i.e., in a full rotation, there are $n$ wheel bars passing at a given angle). Therefore, writing $\omega = {v\over r}$ with $v$ being the car speed and $r$ the wheel radius (here I am assuming pure rolling of the wheel), when $$ v > {{\pi\nu r}\over{n} } $$ we may assume that some kind of aliasing took place, i.e., I guess you would be unable to reconstruct correctly the wheel motion.
So assuming that a typical wheel has 10 bars and a radius of about 0.3 meters and your eye samples at ~30 Hz (typical frame rate of most first person shooter videogames, so it may be used as an upper limit since there one has complete illusion of movement), a rule of thumb calculation yields about 30 meters/second as a reasonable threshold speed for aliasing phenomena.