rmclain
Black Belt
It is not online anywhere that I know of. I just have the receipt paperwork from the L of Congress for the study. Let me check, I'm sure I still have it one one of my hard drives if not printed collecting dust somewhere.
R. McLain
Basic Physics
- Thread starter DArnold
- Start date
It is not online anywhere that I know of. I just have the receipt paperwork from the L of Congress for the study. Let me check, I'm sure I still have it one one of my hard drives if not printed collecting dust somewhere.
R. McLain
It is not online anywhere that I know of. I just have the receipt paperwork from the L of Congress for the study. Let me check, I'm sure I still have it one one of my hard drives if not printed collecting dust somewhere.
R. McLain
Sir, if you are willing to share electronic copies, I would be interested as well.
Thanks
It is not online anywhere that I know of. I just have the receipt paperwork from the L of Congress for the study. Let me check, I'm sure I still have it one one of my hard drives if not printed collecting dust somewhere.
R. McLain
Much appreciated, RM!
Heh heh...it's not that we don't notice the real world, Tez... it's more like, we'd just as soon disregard it... :lol:
The Ground is not your enemy. Your enemy is the deceleration rate and or the develeration trauma.
Yes... it's not the fall that worries me; it's the sudden sharp stop at the bottom!
But to get back to the original discussion, yes, I do discuss the difference between acceleration and speed, as relates to velocity, with my students - not in as much engineering detail as has been presented here, but in general terms, with demonstrations, as it helps them to understand why I want them to perform techniques in a certain way. I don't necessarily have this discussion with white belts - but by green or blue belt, all of my students will know the general principles of physics as applied to kicking and punching, and how those principles affect their power.
Speed IS equal to velocity. It's also referred to as the distance traveled over time (distance over time or rise over run). When the same distance is covered faster then previously measured, then you are accelerating. One has to accerate his/her car up to the desired speed.
Basic math is so coool. Oh, I would argue this is beginner algebra instead of physics.
No, GC, not quite. Speed is a scalar; it's strictly a magnitude. Velocity is a vector. It makes a big difference (just like the difference between power and work is a big difference...)
FieldDiscipline
2nd Black Belt
Another engineer's opinion, Exile is correct. As bleeding usual :mst:
Thanks, FD, and I hope GC didn't think I was being abrupt; I had to sneak in a post because We are Cleaning the Basement and that's all I could fit in... savvy? :wink1: (as Captain Jack Sparrow would say).The difference in the case of speed and velocity emerges really clearly when you look at circular motion of some mass at a constant speed. Is the velocity constant too? No, because the velocity has two components, one parallel to the tangent of the motion and one perpendicular to the motion, the normal component. The tangential component is constant, but the normal component isn't (hence, the time derivative of the normal component of velocity doesn't vanish). So a mass orbiting in a circle with constant speed has a non-null acceleration, which is why torque exists even when a mass is rotating at constant speed.
There's one other thing: I don't think this stuff is reducible, if that's the word, to basic mathematics. The whole of classical Newtonian mechanics rests on the central observation that momentum, the vector quantity mv, usually written p, is conserved in any closed interaction. That is, the time derivative of p is zero. So that means that where momentum is not conserved, the system is not closed, and the intervention from outside the system is characterized as a force. Since the measure of the force is the degree to which the time derivative of momentum differs from zero, the conservation of momentum entails that F = dp/dt, which is just another way of writing Newton's `second law', which isn't really a law, but rather a claim about a particular physical quantity—i.e., that it doesn't change over time in an isolated system. But that needn't be the case. It's a fact about the universe, not about mathematics. The fact that both linear and angular momentum are conserved quantities, among others conserved quantities, corresponds to constraints upon the universe we happen to live in. It's not entailed either by the foundations—or any particular elaborations of the foundations—of mathematics. Classical physics relies on mathematical relationships, but its central premise, the conservation of momentum, is just a fact about how things are....
Good stuff people!
This thread reminds me of a paper I wrote for an English 101 class a long time ago. The assignment was something like 'using only one page with standard formatting, compare two things which appear to be the same or similar, but are different'. Fortunately, I was taking a physics class at the same time and we recently discussed speed v. velocity. Whenever I could, I got my classes to overlap, even English and physics.
My example included a car going 35 mph and continued going 35 mph into a curve and that the speed remained constant while the velocity changed. If I recall, I even included the part that the change in direction was considered acceleration despite the speed remaining the same. Wow, it's been a while.
This thread reminds me of a paper I wrote for an English 101 class a long time ago. The assignment was something like 'using only one page with standard formatting, compare two things which appear to be the same or similar, but are different'. Fortunately, I was taking a physics class at the same time and we recently discussed speed v. velocity. Whenever I could, I got my classes to overlap, even English and physics.
My example included a car going 35 mph and continued going 35 mph into a curve and that the speed remained constant while the velocity changed. If I recall, I even included the part that the change in direction was considered acceleration despite the speed remaining the same. Wow, it's been a while.
Good stuff people!
This thread reminds me of a paper I wrote for an English 101 class a long time ago. The assignment was something like 'using only one page with standard formatting, compare two things which appear to be the same or similar, but are different'. Fortunately, I was taking a physics class at the same time and we recently discussed speed v. velocity. Whenever I could, I got my classes to overlap, even English and physics.
My example included a car going 35 mph and continued going 35 mph into a curve and that the speed remained constant while the velocity changed. If I recall, I even included the part that the change in direction was considered acceleration despite the speed remaining the same. Wow, it's been a while.
It's such a good example, though, isn't it!
gnrail
Yellow Belt
I am not sure if I should apologize to the rest of the readership for sending this thread so far off into the realm of Math and physics but after 17 years as a professional engineer the mentoring side of the job kicks in sometimes. My wife is a math and physics professor at our local college and she was impressed with all the high level theory that suddenly popped up here.
One thing that I see coming out of the discussion is that as an instructor you need to tailor your instructional methods to your individual students. Every one is at a different level in life and has different life experiences. So while a highly technical physic's explanation will help some one like me understand why we punch the way we do in class it will not work for my 9 year old son who is learning the same curriculum (he started karate first and out ranked me for a while)
Another thing I realized through this discussion
Work can sometimes be defined as Force times distance
So F= M*A and W = F*D then W= M*A*D and that is bad so we should do no work
artyon:
One thing that I see coming out of the discussion is that as an instructor you need to tailor your instructional methods to your individual students. Every one is at a different level in life and has different life experiences. So while a highly technical physic's explanation will help some one like me understand why we punch the way we do in class it will not work for my 9 year old son who is learning the same curriculum (he started karate first and out ranked me for a while)
Another thing I realized through this discussion
Work can sometimes be defined as Force times distance
So F= M*A and W = F*D then W= M*A*D and that is bad so we should do no work
artyon:
Why on earth should you apologize, gnr??
Any discussion that brings in physics hinges on the correctness of details—getting both the math right (aka `equation-slinging' :lol
and the physical relationships right. You can't do real physics or real engineering without that. My old undergrad advisor liked to say that there was just one way to be right in physics but many ways to be wrong, and while I'm not sure he was literally right (you can solve physics problems using the Newtonian, Lagrangian or Hamiltonian formulations, and while they're all mathematically equivalent, usually one of them is much easier to use than any of the others in a given physical situation), his basic point was dead on. It was a message that I in particular badly needed to learn...Right. Everyone has a different `sweet spot', as the tennis players say, so far as understanding goes...
IAnother thing I realized through this discussion
Work can sometimes be defined as Force times distance
So F= M*A and W = F*D then W= M*A*D and that is bad so we should do no work
:roflmao:
I swear I said something about the dueling slide rules and the physics of a punch actually being pretty complicated...
I guess I should've use a hundred words instead! LOL
Actually, this highlights the dangers of a lay person trying to oversimplify something that's already been oversimplified... I see it all the time in shows like CSI; lots of the stuff they show just don't work so easy in the real world.
You did indeed, jks... and that's the truth! It's the main reason why I think that there's less chance of baffling the poor student if you talk mostly about how things feel and what they're experiencing—actual sensations they can immediately recognize—than by trying to abstract too far from those immediate sensations...
I can't help it... I just type what the voices in my head tell me to type...
Yeah, and this was a point that Kosho G. also made: it's too easy to bugger things up when you're trying to apply physical models, which are based on all kinds of idealizations, to real event in the real world. Find me a frictionless ramp or an infinitely long cylinder or any of the other stock-in-trade of physics textbooks and... you're gonna be very, very rich!
Good stuff people!
This thread reminds me of a paper I wrote for an English 101 class a long time ago. The assignment was something like 'using only one page with standard formatting, compare two things which appear to be the same or similar, but are different'. Fortunately, I was taking a physics class at the same time and we recently discussed speed v. velocity. Whenever I could, I got my classes to overlap, even English and physics.
My example included a car going 35 mph and continued going 35 mph into a curve and that the speed remained constant while the velocity changed. If I recall, I even included the part that the change in direction was considered acceleration despite the speed remaining the same. Wow, it's been a while.
I did the same things. I wrote a paper on Sugar substitutes that also fit in with my Chem work.
Yes prof., I recall my physics classes. I was just trying to give the 'dirty' relation. But thanks for calling me out on it. I'm humbled.
So, would I get partial credit if I said speed (w/ a constant direction) is closely related to (positive) velocity in the same direction? That is, velocity in the same direction as the speeding object?
Well, I figured you knew, but I had the feeling that it might become a target for adverse comment if it were left where it was. :wink1:
You get full credit, GC! Speed seems to be used to denote the magnitude of the tangential velocity component. In the case of linear motion, that's all there is. In the case of curvilinear motion, it's the component in the direction of the tangent to the path.
