Recent content by ufarad

I taught myself the pre-calculus math topics using a textbook titled "Precalculus" by Larson & Hostetler. https://www.amazon.com/dp/0618052852/?tag=pfamazon01-20 is a different, newer edition than the one I used, and at the typing of this response by me, there's a used one apparently for $US 11.40.

My physics textbook had, for instance, a velocity written as 5.0 \hat{i} + 3.6 \hat{j} - 8.4 \hat{z} m/s. That is, numbers followed by unit vector letters with hats on them and after all three, the unit.

The force of friction is equal to the normal force multiplied by the kinetic coefficient of friction. The normal force is equal (in magnitude, but opposite in direction) to the force pulling the object down, namely, mg.

I would say you're looking for \mu k, as \mu s is only applicable when masses have zero velocity. To solve for \mu s, you need to be told how much force is being applied to a body at rest when it just starts to budge.

His initial kinetic energy must be equal to his final kinetic energy plus the amount of energy lost due to friction. So the amount of energy lost to friction is E_{ki} - E_{kf} which is equal to mg\mu d. Now you were given time instead of distance, but if you can assume constant deceleration...

I'd say yes, it takes more force to push something to a stop than it does to push something down to 8.0 m/s if you get to assume that the time duration of 0.40 s is the same in both cases.

If the author of the problem has a tacit assumption that the bridge supports cannot move at all and that the car would not have any ricocheting velocity (which would seem to need to be specified, since this can easily be assumed not to be an elastic collision), then all the kinetic energy of the...

My friend, that is why I posted this thought in the philosophy section.

Is there any reason that there could not be particles in the same universe as us that had their own fundamental forces of strong nuclear, electroweak, and gravity equivalent to those we know and love but which did not affect our particles nor ours theirs all around us (i.e., totally undetectable...

Does there exist a known process to devulcanize rubber (i.e., getting out all the sulfur crosslinks from the polymer chains) and get out of the process rubber that can be revulcanized? Or does one big slash on a tire mean that 20-30 pounds of rubber can never be used for making tires again?

I have these little metal rings used for holding eggs in while you fry them to keep them from running all over the place. These metal rings have stainless steel loop handles that stick up which get so hot as to be untouchable with unprotected fingers. I want to coat the top part of those...

What is it about graphite leads that make them so much better for electrolysis than, say, copper leads? I tried it both ways, connecting leads to a battery and then sticking them in some water and with the graphite leads there was much more bubbling going on. So what is it about the graphite...