![]() |
| If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|||||||
| Tags: between, relation |
|
|
|
Thread Tools | Display Modes |
|
#1
|
|||
|
|||
|
What's the ratio of an impulse (ft), to the rate of displacement (s/t)
that it causes? Is the impulse (ft) numerically equal to the rate of displacement (s/t) that it causes? Don |
| Ads |
|
#2
|
|||
|
|||
|
What's the ratio of an impulse (ft), to the rate of displacement (s/t)
that it causes? Rate of displacement, is just called velocity which is a function of time v(t). Impulse is the integral of force with respect to time. If force is constant (keeping it simple for Don1), impulse is I = F * (t1-t0). Let t = t1-t0 So I = F*t And F=M*A So I = M*A*t With constant force and mass, we have constant acceleration. Assumimg v(0) = 0, we have v(t) = A*t So I = M*v(t) You asked what is the ratio of impulse I to velocity v(t). So I/v(t) = (M*v(t))/v(t) = M. The ratio you are looking for is just the mass M. Is the impulse (ft) numerically equal to the rate of displacement (s/t) that it causes? No. |
|
#3
|
|||
|
|||
|
What's the ratio of an impulse (ft), to the rate of displacement (s/t)
that it causes? Rate of displacement, is just called velocity which is a function of time v(t). Impulse is the integral of force with respect to time. To make it simpler, just think of impulse as being "change in momentum" (by definition). So it has the same units, dimensions, and meaning as momentum. You know that momentum is mass times velocity (i hope), or p=m*v. You are asking what is the ratio of momentum to velocity, or p/v. Even Don1 should see that this ratio is just mass m. Or maybe not... |
|
#4
|
|||
|
|||
|
"Don1" wrote ...
What's the ratio of an impulse (ft), to the rate of displacement (s/t) that it causes? Is the impulse (ft) numerically equal to the rate of displacement (s/t) that it causes? Impulse equals change in momentum. Impulse equals the product of force and time *only* when the force is constant. Momentum equals mass times velocity. Change in momentum equals final momentum minus initial momentum. Did you loose your introductory physics book? Send me your address and I'll gladly mail several to you, at my own expense. ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
|
#5
|
|||
|
|||
|
Don1 wrote:
What's the ratio of an impulse (ft), to the rate of displacement (s/t) that it causes? Is the impulse (ft) numerically equal to the rate of displacement (s/t) that it causes? Don See: http://scienceworld.wolfram.com/physics/Impulse.html |
|
#6
|
|||
|
|||
|
Herman Trivilino wrote: "Don1" wrote ... What's the ratio of an impulse (ft), to the rate of displacement (s/t) that it causes? Is the impulse (ft) numerically equal to the rate of displacement (s/t) that it causes? Impulse equals change in momentum. Impulse equals the product of force and time *only* when the force is constant. Momentum equals mass times velocity. Change in momentum equals final momentum minus initial momentum. Did you loose your introductory physics book? I think you lost it too. The impulse that causes a change in momentum delta(p) in time delta(t) is equal to the average force over that time interval times delta(t). Force need not to be constant, otherwise Newton's 2nd law would not hold for arbitrary forcing functions, like for instance a gravitational potential field that is a function of position r. Mike Send me your address and I'll gladly mail several to you, at my own expense. ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
|
#7
|
|||
|
|||
|
Sam Wormley wrote:
Don1 wrote: What's the ratio of an impulse (ft), to the rate of displacement (s/t) that it causes? Is the impulse (ft) numerically equal to the rate of displacement (s/t) that it causes? Don See: http://scienceworld.wolfram.com/physics/Impulse.html Oh please Sammy; NOTHING happens instantaneously: Everything takes time. Don |
|
#8
|
|||
|
|||
|
Don1 wrote:
Sam Wormley wrote: Don1 wrote: What's the ratio of an impulse (ft), to the rate of displacement (s/t) that it causes? Is the impulse (ft) numerically equal to the rate of displacement (s/t) that it causes? Don See: http://scienceworld.wolfram.com/physics/Impulse.html Oh please Sammy; NOTHING happens instantaneously: Everything takes time. Don You probably missed (on purpose?) the integration over time 0-tau! |
|
#9
|
|||
|
|||
|
odin wrote:
What's the ratio of an impulse (ft), to the rate of displacement (s/t) that it causes? Rate of displacement, is just called velocity which is a function of time v(t). Impulse is the integral of force with respect to time. If force is constant (keeping it simple for Don1), impulse is I = F * (t1-t0). Let t = t1-t0 So I = F*t And F=M*A So I = M*A*t With constant force and mass, we have constant acceleration. Assumimg v(0) = 0, we have v(t) = A*t So I = M*v(t) You asked what is the ratio of impulse I to velocity v(t). So I/v(t) = (M*v(t))/v(t) = M. The ratio you are looking for is just the mass M. You got it: The ratio ft/(s/t) can be more concisely as m=ft^2/s; which is also equal to 2w/g. Is the impulse (ft) numerically equal to the rate of displacement (s/t) that it causes? No. First you say it does, and now you say it doesn't. Make up my mind will you. Don |
|
#10
|
|||
|
|||
|
You asked what is the ratio of impulse I to velocity v(t).
So I/v(t) = (M*v(t))/v(t) = M. The ratio you are looking for is just the mass M. You got it: The ratio ft/(s/t) can be more concisely as m=ft^2/s; which is also equal to 2w/g. Is the impulse (ft) numerically equal to the rate of displacement (s/t) that it causes? No. First you say it does, and now you say it doesn't. Make up my mind will you. Impulse is not, in general, numerically equal to the rate of displacement. Assuming an initial velocity of zero, they are proportional to eachother. The proprotionality is the mass involved. Given a particular system of units, you can pick the mass carefully to make the impulse numerically equal to the rate of displacement. In that very specific case you would be correct. But for the genrality that you framed your question in, where the initial velocity and the mass involved are arbitrary, the answer to your question is nope. Note that impulse is a delta, if that helps your understanding a bit as well. |
|
| Thread Tools | |
| Display Modes | |
|
|
Similar Threads
|
||||
| Thread | Thread Starter | Forum | Replies | Last Post |
| Energy time uncertainty relation | karan@iitk.ac.in | Physics - General Discussion | 9 | September 15th 05 12:02 AM |
| A Single Relation Electron Theory | Douglas Eagleson | Physics - General Discussion | 2 | July 10th 05 04:20 AM |
| what is the relation between force and energy? | yogesh | Physics - General Discussion | 229 | October 26th 04 02:49 PM |
| relation | MeV | Physics - General Discussion | 3 | July 28th 04 08:49 PM |
| A new equivalence relation? | MCKAY john | Physics - General Discussion | 0 | May 27th 04 10:42 AM |