SiRaLeX Posted October 25, 2015 Share Posted October 25, 2015 Dear pupils of CnCNet, From my physics studies I know the formula to calculate velocity: v = delta x / delta t Where x is the distance traveled and t the time in which the distance was traveled. So, say I ran 600 meters in 1.5 minutes (= 90 seconds). My mean velocity would have been: v = 600 m / 90 s v = 6.67 m/s (= 24 km/h) Which makes perfect sense. Now comes the interesting part. Say I wanted to calculate my acceleration, the formula would be: a = delta v / delta t Where v is the difference in velocity and t the time in which said difference was attained. So, say it takes me 5 seconds to reach my final speed of 6.67 m/s, my acceleration would be: a = (6.67 m/s) / (5 s) a = 1.33 m/(s^2) What the fuck does this tell me? My acceleration is 1.33 m/(s²), cool, so now, what can I make out of it? I mean I know what a m² (square meter) is. But what the fuck is an s² (square second)? I just can't make anything out of it. Thanks, SiRaLeX Link to comment Share on other sites More sharing options...
Milkey Wilkey Posted October 25, 2015 Share Posted October 25, 2015 I don't know where you live, but in my country it's a basic school knowledge. just draw a function of y(x2) and it will explain you a lot. Link to comment Share on other sites More sharing options...
SiRaLeX Posted October 25, 2015 Author Share Posted October 25, 2015 I don't know where you live, but in my country it's a basic school knowledge. just draw a function of y(x2) and it will explain you a lot. I live in Germany. Where do you live? What do you mean with y(x²)? We're talking about 1.33 m/(s²), I don't really see how y(x²) is applicable here? Link to comment Share on other sites More sharing options...
Milkey Wilkey Posted October 25, 2015 Share Posted October 25, 2015 in Belarus. ok, let's look at this from another spot m/s2 = (m/s)/s that means how much you speed will increase every second in your case it will increase by 1.33 m/s every second just don't try to imagine square seconds, math is an abstract science Link to comment Share on other sites More sharing options...
SiRaLeX Posted October 25, 2015 Author Share Posted October 25, 2015 Well, to be quite frank, it doesn't make any sense to me. Can you help me draw that graph?! This is the only thing I managed to get done, which makes sense to me (see attachment), it's about velocity not acceleration. Link to comment Share on other sites More sharing options...
Jacko Posted October 25, 2015 Share Posted October 25, 2015 Acceleration is the rate of change of velocity. A square Second is just a sort of abstract feature that comes out of what acceleration is, theres no real physical way to explain it other than that. Try understanding what this unit is: m-3 kg-1 s4 A2. (That particular unit is the permittivity of free space, mostly involved with electromagnetism) What you will find a lot in Physics is constants and variables with units that from an individual view, make zero sense, but are derived from unit cancelling, or from calculation (like how Acceleration comes to be ms-2) But your calculation of acceleration is fine (its constant so its not complicated) using x,v,a,t (distance, speed, acceleration, time) v = dx/dt, and a = dv/dt. Your number 1.33 tells you in one second your speed increases by 1.33ms-1 and that you move 1.33m Link to comment Share on other sites More sharing options...
SiRaLeX Posted October 25, 2015 Author Share Posted October 25, 2015 Acceleration is the rate of change of velocity. That's correct! Thanks so much for your post - I'll try to understand it. In the meantime I drew the acceleration graph (acceleration from 0 m/s to 6.67 m/s in 5 seconds). I still don't have much of an idea how to draw the s² graph though. Link to comment Share on other sites More sharing options...
Jacko Posted October 25, 2015 Share Posted October 25, 2015 you don't plot vs t2 you plot x against t and v against t. The acceleration becomes obvious in the v against t because its a straight line, and the gradient (dv/dt) is your acceleration. In fact plotting against t2 is harder because then the graph becomes non-linear, and thats just pointless extra work. Link to comment Share on other sites More sharing options...
Milkey Wilkey Posted October 26, 2015 Share Posted October 26, 2015 you don't plot vs t2 you plot x against t and v against t. The acceleration becomes obvious in the v against t because its a straight line, and the gradient (dv/dt) is your acceleration. In fact plotting against t2 is harder because then the graph becomes non-linear, and thats just pointless extra work. ahh, you're right, that explanation is much simplier. I just used to make that kind of things in matlab Link to comment Share on other sites More sharing options...
X3M Posted October 26, 2015 Share Posted October 26, 2015 He is beating me to it every time. Just listen to Jacko Link to comment Share on other sites More sharing options...
SiRaLeX Posted October 26, 2015 Author Share Posted October 26, 2015 So are my drawings correct? Should I perhaps switch the axes? Drawing a graph with t² on one side is pointless? You guys are very knowledgeable, there's no doubt about it! Link to comment Share on other sites More sharing options...
X3M Posted October 26, 2015 Share Posted October 26, 2015 When you have troubles with Chemistry, ask me. Any way, could you please post the questions instead? If we know the correct questions, we can give you the right answers. One might shout, that both graphs are incorrect. But the first one is depending on what the exact question was. I remember that we had to make retarded graphs first for "learning" process. Then we had to discard and start over. Such lovely times. Link to comment Share on other sites More sharing options...
Nyerguds Posted October 26, 2015 Share Posted October 26, 2015 Man, stop trying to make us do your homework. This is, again, bloody simple. "m/s" is velocity. "m/s²" is "(m/s)/s". In other words, velocity per second. Also known as, acceleration Link to comment Share on other sites More sharing options...
SiRaLeX Posted October 27, 2015 Author Share Posted October 27, 2015 Man, stop trying to make us do your homework. This is, again, bloody simple. "m/s" is velocity. "m/s²" is "(m/s)/s". In other words, velocity per second. Also known as, acceleration Oh, really? Didn't know what velocity and acceleration was. That's why I was able to calculate them. :roll: You're very smart aren't you? Took you a while to come up with that, though and no, it's not homework. It's a bogus example asked to understand the concept of s², whereas the better way to put it is indeed (m/s)/s as s² on itself just doesn't make any sense (I believe) - I know that now. Milkey Wilkey and Jacko already explained that very well. When I search in Google for "square second" the very first results it gives me are "meter per second squared". Just an example I made up, not homework or do you think dividing 6 by 1.5 is homework I have to do? Not even related to homework. Homework would be about Newtonian dynamics, if there was any homework. Link to comment Share on other sites More sharing options...
cn2mc Posted October 27, 2015 Share Posted October 27, 2015 Homework would be about Newtonian dynamics, if there was any homework. Wouldn't that be exactly that part of high-school Newton that covers acceleration? Link to comment Share on other sites More sharing options...
SiRaLeX Posted October 27, 2015 Author Share Posted October 27, 2015 Wouldn't that be exactly that part of high-school Newton that covers acceleration? Don't think so: https://en.wikipedia.org/wiki/Newtonian_dynamics Link to comment Share on other sites More sharing options...
cn2mc Posted October 27, 2015 Share Posted October 27, 2015 Read the first two paragraphs of your own wiki link and check what the Second law is about again. Link to comment Share on other sites More sharing options...
SiRaLeX Posted October 27, 2015 Author Share Posted October 27, 2015 In physics, the Newtonian dynamics is understood as the dynamics of a particle or a small body according to Newton's laws of motion. Typically, the Newtonian dynamics occurs in a three-dimensional Euclidean space, which is flat. However, in mathematics Newton's laws of motion can be generalized to multidimensional and curved spaces. Often the term Newtonian dynamics is narrowed to Newton's second law ma = F. The vector sum of the external forces F on an object is equal to the mass m of that object multiplied by the acceleration vector a of the object: F = ma. Link to comment Share on other sites More sharing options...
Nyerguds Posted October 27, 2015 Share Posted October 27, 2015 The vector sum of the external forces F on an object is equal to the mass m of that object multiplied by the acceleration vector a of the object: F = ma. There's your m/s² Link to comment Share on other sites More sharing options...
X3M Posted October 27, 2015 Share Posted October 27, 2015 Hell yeah, kg*m/s² Or in other words. N When you put some force into things you go... ... ... Nnnnnnnnnnnnnnnnnnnnnn!!!!! Link to comment Share on other sites More sharing options...
SiRaLeX Posted October 27, 2015 Author Share Posted October 27, 2015 You're right! 1 N = 1 kg * m/s² I prefer not to know the definition of a Newton but rather that Newton is supposed to come out of a formula I'm inserting values into. Link to comment Share on other sites More sharing options...
XXxPrePxX Posted October 28, 2015 Share Posted October 28, 2015 Alex, if you want to understand this on a simple level rather than take all the time to decipher various wiki's and such, check this out: Link: https://www.khanacademy.org/science/physics/one-dimensional-motion Now go to the part where it says "What are acceleration vs. time graphs" Note: You can also check out the "What are velocity vs. time graphs" I'm pretty sure this will cover your questions. Link to comment Share on other sites More sharing options...
SiRaLeX Posted October 28, 2015 Author Share Posted October 28, 2015 Awesome, mate! Found it: https://www.khanacademy.org/science/physics/one-dimensional-motion/acceleration-tutorial/a/what-are-acceleration-vs-time-graphs Thank you so much, PreP! Link to comment Share on other sites More sharing options...
Eisengeist Posted November 7, 2015 Share Posted November 7, 2015 https://www.google.com/search?q=e%3Dmc+hammer&biw=1093&bih=517&tbm=isch&tbo=u&source=univ&sa=X&sqi=2&ved=0CCkQsARqFQoTCJPVnfCO_cgCFQGmHgodqS0MYw Link to comment Share on other sites More sharing options...
SiRaLeX Posted November 7, 2015 Author Share Posted November 7, 2015 https://www.google.com/search?q=e%3Dmc+hammer&biw=1093&bih=517&tbm=isch&tbo=u&source=univ&sa=X&sqi=2&ved=0CCkQsARqFQoTCJPVnfCO_cgCFQGmHgodqS0MYw Haha, can't touch this! Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now