Team-BHP - The right Gear shifts?

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I'm sorry, but according to you, torque is work done.

Now, W = F s cos theta. And F = m a.

a is acceleration. As we all know, acceleration is a factor of both time and movement. Time since a = (v-u)/t, and movement, since if you have a finite value for a, some sort of displacement has occured.

So when you apply torque to a rusted bolt, whats accelerating? Or are you trying to prove that torque is not being produced in this case? (which you can't)

Torque is not acceleration.....but it can be used to create acceleration.

But, the fact remains that torque can exist without time or movement.

Shan2nu

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Originally Posted by The Wolf (Post 417570)

V1p3r: Dude torque is the measure of a force's tendency to produce torsion and rotation about an axis, irrespective of howmuch rotation it is causing!!!

Well, torque is useless without rotation!... does NOT mean there is NO torque possible without rotation.

You don't have rotation your torque is useless!. AND if you have rotation... what matters is how much rotation!.... AND if you have torque and rotation (the only useful combination).... then you are actually talking about power (and thats what I said).

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Originally Posted by SLK (Post 417576)

LOL!!! Dude can you pls tell me what rotation are you speaking about?? Is it the crank or the wheels???

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Exactly, what i said. You don't need RPM to have torque but you need it to have power.

Torque is produced at "19000rpm" in a F1 engine.......as well as at "0rpm" when you're stuck with a rusted bolt.

Shan2nu

Quote:

Originally Posted by The Wolf (Post 417579)

LOL!!! Dude can you pls tell me what rotation are you speaking about?? Is it the crank or the wheels???

LOL... since its all measured at the crank .... then we talk about the crank.

BUT since Shan2nu said.. its not R P M!!!... but any R would do... I used the 'R' to be on the safer side!

Quote:

Originally Posted by SLK (Post 417583)

LOL... since its all measured at the crank .... then we talk about the crank.

BUT since Shan2nu said.. its not R P M!!!... but any R would do... I used the 'R' to be on the safer side!

Slk, well then if the crank isnt moving does it mean the torque isnt being produced??? Just put a lighter crank and you will know if there is any torque being produced there at all....you get my point??

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Originally Posted by Shan2nu (Post 417571)

Torque is not being produced. Just like when you hold a 100 kg load in your arms, they may ache, but you are not doing any work.

Torque is a function of acceleration. It can also be defined as the rate of change of angular momentum, ie T = dL/dt . If you look at that, you will realise that you CANNOT have torque without a relation to time and space. In fact, in physics, you cannot have ANYTHING without a relation to time and space.

I suggest you look at this definition. It will help you out.

Quote:

Originally Posted by The Wolf (Post 417587)

Ahh, I get your point .... but... its not about that .. the torque is inadequate to move a crank. It was just about the fact.. that if its not rotating... its no good use... you can't move your car an inch.

the same 'x' amount of toque at 'y' rpm will help you move your car at some speed.... and that same 'x' torque at '2y' rpm would give more speed.... and the same 'x' torque at 0 rpm won't give you anything. (why is it at 0 rpm?... coz there is an opposite force not letting you move)

Its all theory ... lets not put lighter cranks!

Quote:

Torque is not being produced. Just like when you hold a 100 kg load in your arms, they may ache, but you are not doing any work.

Torque is a function of acceleration. It can also be defined as the rate of change of angular momentum, ie T = dL/dt . If you look at that, you will realise that you CANNOT have torque without a relation to time and space. In fact, in physics, you cannot have ANYTHING without a relation to time and space.

Here's something from the same page.

"Steam engines and electric motors tend to produce maximum torque close to zero rpm, with the torque diminishing as rotational speed rises (due to increasing friction and other constraints). Therefore, these types of engines usually have quite different types of drivetrains from internal combustion engines."

And here's more (similar to what i explained)

"Torque is a twisting force applied to an object, like a wheel or a crankshaft. Note that motion is not required for torque to exist! If you stand on a lug wrench that is on a frozen lug bolt, you are applying a torque to that bolt even though there may be no movement. For our purposes, we will consider that torque is measured in pounds-force feet (lbf-ft) meaning the equivalent of a given force, in pounds, acting on the end of a lever of length in feet. For example, standing with 180 pounds body weight on a lug wrench one foot long yields 180 lbf-ft of torque. A child of 90 pounds standing on a two-foot lug wrench applies the same torque. "

Source - Torque and Power

Torque is force * distance where force is the pessure exerted on the spanner and the distance is the lenght of the spanner.

You're getting confused between existance of torque at 0rpm and it's use at 0rpm.

Shan2nu

^^ For n00bs like me...can you give examples like what Shan2nu gave (about the spanner and the nut)..thats helps non-techie nuts like us understand and learn a little what the hell you guys are talking about..

OT: I started reading this thread hoping that i would learn to shift gears in a correct manner by seeing the title (i am very n00b driver)...but it looks like I can give a Physics graduation exam with all this technology...in a way its good, but would be better with good plain vanilla examples

I'd like to know how difficult it is to sown shift to 1st at really slow speeds.

Usually there are a few speedbreakers that one needs to negotiate in 1st gear. While approaching the hump at a really slow speed, many a times the car refuses to slot into 1st. I generally have to completely stop the car shift to 1st then go over. shifting to 1st even when the car is really slow just about to stop is not possible.

Also, how does one know if the synchro rings are worn out?