Running Radar?

[aunt betty]

Usually, when someone is stuck in a ditch, it's easier to push them out than to pull them out. That's why you see people doing it all the time.

Someone needs to tell nanuck72 about this. Them Alaskan dogs he has have been doing it all wrong for thousands of years.

[aunt betty]

Unrelated story...but a little bit related.
Many years ago a big rig semi got into the median on I-57 near Pesotum, Illinois. Two large wreckers failed at getting the truck unstuck. Median was flooded and was "soup".
The solution:
A guy somewhere owned an ELEPHANT. That sucker pulled the truck out no sweat.

[Woody]

Usually, when someone is stuck in a ditch, it's easier to push them out than to pull them out. That's why you see people doing it all the time.

Is that why they pull snow plows instead of push them?

[DeadEye_Dan]

Usually, when someone is stuck in a ditch, it's easier to push them out than to pull them out. That's why you see people doing it all the time.

Is that why they pull snow plows instead of push them?

You ever see a plow on a 2wd truck??

[Woody]

Usually, when someone is stuck in a ditch, it's easier to push them out than to pull them out. That's why you see people doing it all the time.

Is that why they pull snow plows instead of push them?

You ever see a plow on a 2wd truck??

Does a six toed man juke better, when barefoot in the middle of November or March?

[Goldfish]

Usually, when someone is stuck in a ditch, it's easier to push them out than to pull them out. That's why you see people doing it all the time.

Is that why they pull snow plows instead of push them?

You ever see a plow on a 2wd truck??

Seen it on a beetle.


Throwing an ebrake is a necessity for front wheel drive cars. That gets the car pointed in the direction you want to go so you can punch the gas to pull you forward. You just don't need to use it for rear wheel, just hit the pedal on the right.

Jehler gets having fun, and I'd bet he does it no matter the drive orientation. Betty doesn't really get it tho. Assa just wants to go, not play around (that would burn gas, which costs money).

Sometimes not staying in the grip is the fastest way. Tough to do in a front wheel drive, and will always be beat by rear wheel, and both can be eclipsed by all wheel, but that's not what you guys are taking about. You guys are talking about remaining in control, and to do so is boring and slow and to be used for the idiots that can't hardly handle parking in an empty lot, much less diving in adverse conditions.

[aunt betty]

Can't afford accidents, insurance, hospital bills...
You know, old people shit.

I outlived quite a few dumbasses from school that talked the talk but missed a curve and drove straight down a mountain. More than one or two. If you only knew how many of my friends funerals I have been to...
Really.

[Woody]

How does friction relate to automobiles?

In some places, especially in the winter, you must keep friction in your mind constantly as you drive, in order to avoid an accident. You have to limit your speed in order to be able to stop at a reasonable distance, and to negotiate curves.

Braking distance can be calculated using the equation d = V^2 / 2gµ

Where:
d = Braking Distance
g = Acceleration due to gravity (9.80 m/sec^2)
V = Initial vehicle speed (m/sec)
µ = Coefficient of friction between the tires and the roadway

Notice that initial velocity is squared; this means that if you travel twice as fast, your stopping distance is squared, not doubled. This is why the two second rule ("travel at a speed so that two seconds pass between the moment the car in front of you passes a landmark and the moment you pass the same landmark") is not valid for high speeds; your stopping distance increases exponentially as you go faster.

A higher coefficient of friction decreases your stopping distance. It is better, therefore, for your tire to be using static friction rather than kinetic friction. If the tire is rolling along so that the surface touching the ground is never sliding, then static friction is acting to slow the car. If the wheels are locked and sliding, then kinetic friction is acting to slow the car. In order to utilize static friction when you need to stop quickly, there are several options. You can attempt to apply just enough brake to stay within the static range of friction and not too much to lock the tires. This is the best option, in terms of stopping you the quickest, but it can be difficult to be that precise with the brake. It can be especially difficult if you are about to hit a moose. Another option is pumping the brake, which has the effect of alternating the use of kinetic and static friction as the wheels lock and unlock. This is not quite as efficient, but easier to do in an emergency. A final option is to have your car take care of the braking for you, through antilock brakes or more sophisticated computer-controlled means. Antilock brakes do the same thing as you do; pump the brakes. The best solution is, of course, to drive slower.

Traveling around a curve causes you to experience a slightly different set of forces, as you must deal with the tendency for a car to want to travel straight ahead. This is explained by Newton's 1st law: an object will not change velocity without a force acting on it. In this case, you are causing the car to change lateral velocity and move to the side by applying frictional force from the tires. If the tires don't have a coefficient of friction large enough to provide the force needed to move the car laterally, then you slide straight forward and off the road.



Usually, the tires must maintain static friction in order to turn the car. That limits the maximum speed to a rate at which the tires do not slip. The equation that models this situation is:

Vmax = square root of (µ(static) g r)

Where:
Vmax = Maximum velocity
g = Acceleration due to gravity (9.80 m/sec^2)
r = Radius of curve
µ = Coefficient of static friction

If you are traveling around a curve with a radius of 10 meters and no snow or rain, Vmax = square root of (1.00 * 9.80 m/sec^2 * 10.0m) = 5.4 m/sec, which is about 22.1 mph. Any faster and the tires would slide.

If you are traveling around a curve with a radius of 10 meters on a snowy day, Vmax = square root of (0.30 * 9.80 m/sec^2 * 10.0m) = 5.4 m/sec, which is about 12.1 mph.

Betty, what would be Vmax around the curve in snowy conditions, if the drive wheels are powered and therefore the car is using kinetic friction to turn instead of static friction?

[aunt betty]

You dumbass. Static friction in a rolling wheel? Think about what you post.

[aunt betty]

Did you take dynamics and pass? Go do it over.

[aunt betty]

Need some undergrad books for engineering?

[Woody]

You dumbass. Static friction in a rolling wheel? Think about what you post.

I could be wrong Betty, but when your tire is rolling with the road the tire rubber isn't moving with respect to the road. Hence with tires rolling, you use static friction. But under power the tire is being spun by a force other than the road so the rubber is moving with respect to the road... kinetic friction.

[aunt betty]

Static means not in motion.
Look it up.

[aunt betty]

Salt dont work above 400' above sea level...
U said that.
I quit believing you or taking u seriously right then.
Its fun arguing with u though.

[Woody]

Static means not in motion.
Look it up.

no it means not in motion with respect to a certain object.

I'm sitting still at my desk, am I moving?

[Woody]

Salt dont work above 400' above sea level...
U said that.
I quit believing you or taking u seriously right then.
Its fun arguing with u though.

: over your head smiley :

[aunt betty]

Your an engineer but not trying to prove anything...
Do you realize that engineers require proof of everything and don't just simply believe when told something new or different?
An engineer proves things and wants to be shown the proof. You amaze me with the silly comments. Its funny as hell.

[aunt betty]

MIT
Stanford
California (Berkley)
California Institute of Technology
Georgia Institute of Technology
And #5 is UIUC.
My alma mater.

The chart only goes up to ten. You went to LSU...right?

[aunt betty]

Cars slide around curves. It is not perceptible yet they do. If your static friction theory were true..tires would never wear out.
Look at a track closely by walking around it. Inspect the pavement. Its got a layer of tire rubber on it.
Assuming static is something undergrads do in order to understand concepts. In reality..static ends once you're moving.

[aunt betty]

Tell u what. I'll give you a silver bullet. Can't believe you ain't used it yet.

If I were u, I'd be saying stuff like "how can a guy that can't count past 18 do calc and get a degree?"

Ha!

[Woody]

You are taking me to serious, Betty, and it is making messing with you not fun.

By the way it was a trick question... can you figure out why?

[aunt betty]

Static means not in motion.
Look it up.

no it means not in motion with respect to a certain object.

I'm sitting still at my desk, am I moving?

Yes. You are in constant motion until you die.

[3geese4me]

Aliens

[aunt betty]

Had dreams that I was abducted at age 6. Quit watching Lost in Space and it quit...
Maybe.

[assateague]

Aliens

[Woody]

Static means not in motion.
Look it up.

no it means not in motion with respect to a certain object.

I'm sitting still at my desk, am I moving?

Yes. You are in constant motion until you die.

Depending on your definition of "you" a person is in constant motion until well after death.

[The Duck Hammer]

Aliens

[Woody]

Aliens

[aunt betty]

Static means not in motion.
Look it up.

no it means not in motion with respect to a certain object.

I'm sitting still at my desk, am I moving?

Yes. You are in constant motion until you die.

Depending on your definition of "you" a person is in constant motion until well after death.

Relative to the surface of the earth...blah blah.
I gotcha. Nothing is static.

[Feelin' Fowl]

Is static, static?