#### Velocity Time Graphs, Acceleration & Position Time Graphs - Physics - By The Organic Chemistry Tutor

00:00 | in this video , we're gonna go over motion graphs | |

00:03 | . We're gonna talk about position , time graphs , | |

00:05 | velocity , time graphs and acceleration time graphs . Now | |

00:10 | there's two concepts that need to be familiar with the | |

00:13 | slope in the area . The slope is associated with | |

00:17 | division . The area is associated with multiplication . Perhaps | |

00:23 | an algebra . You've seen the slope represented by the | |

00:26 | letter M . The slope is calculated by dividing the | |

00:32 | change in Y by the change in X . So | |

00:36 | when you're calculating slope , you're using division . Now | |

00:40 | , let's say if we want to find the area | |

00:43 | as This rectangular segment , Let's call it segment two | |

00:49 | . Mhm . To find the area , we need | |

00:52 | to multiply the less by the west . In this | |

00:56 | case we're multiplying the Y values by the X values | |

01:00 | . So this would be the change in X . | |

01:02 | That would be like the whiff of that rectangle . | |

01:06 | And this is the change in Y . Which would | |

01:08 | be the height of the rectangle . If we multiply | |

01:10 | those two , that will give us area . So | |

01:14 | associate area with multiplication , but slope with division . | |

01:22 | In algebra you've seen this equation for slope , It's | |

01:25 | the change in Y . Which is Y tu minus | |

01:28 | Y . One divided by the change in X , | |

01:31 | which is X two -X . 1 . And you've | |

01:34 | seen this equation for area areas , lifetimes with Wendell | |

01:38 | from rectangle . So make sure you understand those concepts | |

01:43 | . Now let's consider three common time graphs that you | |

01:46 | can encounter . The 1st 1 is the position time | |

01:49 | graph . Typically it's going to be X versus team | |

01:52 | . So when you see that you're dealing with motion | |

01:54 | along the X axis , it could be why versus | |

01:57 | T . If you're dealing with motion along the Y | |

01:59 | axis , vi versus T . Is a velocity time | |

02:03 | graph A versus T . Is the acceleration time graph | |

02:09 | . Now , what do you think the slope of | |

02:12 | a position time graph represents ? Remember slope is the | |

02:18 | change in Y over the change in next . You're | |

02:20 | dealing with division . So if we were to divide | |

02:24 | the position or the change position by the change in | |

02:27 | time , what will we get ? The change in | |

02:31 | position ? Divided by the change in time ? The | |

02:35 | change of position is displacement . If you defied displacement | |

02:41 | , let me just put D for displaced instead of | |

02:42 | writing everything out . But if you were to divide | |

02:45 | displacement by time , you're gonna get the velocity . | |

02:49 | So the slope of a position time graph represents the | |

02:53 | velocity or the instantaneous velocity at that instant . Mhm | |

03:00 | . Mhm . If you calculate the slope that at | |

03:05 | least like an added tangent , you're gonna get an | |

03:06 | instantaneous velocity . If you calculate the slope used in | |

03:10 | two points , you're gonna get an average velocity by | |

03:15 | the way , calculating the slope . At one point | |

03:18 | , it's like finding the slope of the tangent line | |

03:20 | that will give you the instantaneous velocity , calculating the | |

03:23 | slope using two points which is the slope of the | |

03:25 | secret line that will give you the average velocity . | |

03:29 | Nevertheless , the slope of the position time graph gives | |

03:32 | you velocity . So make sure you understand that . | |

03:36 | They might be wondering what is the area of a | |

03:40 | position time graph tells us . The area doesn't tell | |

03:44 | us anything . Remember area is associated with multiplication . | |

03:50 | If we were to multiply the y axis by the | |

03:53 | X axis in this case the change in acts by | |

03:57 | the change in T . We would get meters time | |

03:59 | seconds , which it really doesn't help us in physics | |

04:04 | . So the area for position time draft is not | |

04:07 | really helpful . Yeah . Now , what about the | |

04:10 | velocity time graph ? What does the slope tell us | |

04:15 | ? Yeah . Well , in order to find out | |

04:17 | the slope of velocity time graph , we need to | |

04:20 | use division If we were to divide V by T | |

04:25 | . If we were to take the change in velocity | |

04:27 | and divided by the change in time , what will | |

04:30 | we get velocity typically has a unit to meet us | |

04:34 | for a second . And time is usually in seconds | |

04:38 | . When you divide these two , you get the | |

04:40 | units meters per second squared , what is variable or | |

04:46 | term is associated with the units meters per second squared | |

04:50 | from physics , you've likely seen it as acceleration . | |

04:54 | The slope of a velocity time graph is the acceleration | |

05:01 | . So that's what you need to know when dealing | |

05:02 | with the VT graph . Now , what about area | |

05:09 | ? What does the area of a velocity time graph | |

05:11 | tell you ? So , once again , when you | |

05:14 | think of area think of multiplication . If we were | |

05:17 | to multiply the Y axis by the X axis . | |

05:21 | If we were to multiply V by T , what | |

05:24 | will we get ? Well , let's look at the | |

05:27 | units . Velocity is usually in meters or per second | |

05:31 | or meters over seconds . Time is usually in seconds | |

05:35 | . When you multiply these two , the unit seconds | |

05:38 | cancels . And so we get the unit meters , | |

05:41 | meters is the unit for distance position , displacement . | |

05:48 | But it turns out that when you multiply velocity by | |

05:51 | time you get specifically displacement . So I'm going to | |

05:55 | put dif a displacement speed multiplied by time is distance | |

05:59 | velocity times , time is displacement . So the area | |

06:04 | of a velocity time graph is specifically displacement . Mhm | |

06:12 | . So when dealing with a velocity time graph , | |

06:14 | the acceleration , I mean the slope and the area | |

06:16 | is important . The slope is the acceleration . The | |

06:20 | area is the displacement , displacement is the final position | |

06:25 | , modesty initial position . If you move this term | |

06:29 | to the other side , you're going to get this | |

06:31 | familiar equation . X final is equal to X initial | |

06:34 | plus VT . Let me erase that because I'm going | |

06:39 | to need the space on the right side . So | |

06:43 | hopefully you're taking notes and writing these things down because | |

06:47 | we're gonna use this later in the video . Now | |

06:50 | let's move on to the acceleration time graph . What | |

06:53 | is the slope Of an 80 graph represent ? Wow | |

06:58 | , let's divide . Why buy X . So on | |

07:04 | the Y axis we have acceleration on the X axis | |

07:08 | . We have time . So what is the rate | |

07:11 | of change of acceleration now for most physics classes that | |

07:16 | you're going to counter , you're not going to have | |

07:18 | to worry about it . This is not going to | |

07:20 | be applicable to the everyday common situation . But some | |

07:24 | physics course they do have a value for this and | |

07:29 | this represents a jerk or joke . You can look | |

07:32 | this up in Wikipedia you may see in some textbooks | |

07:36 | , but that's the slope of an acceleration time graph | |

07:40 | on a physics test . If you're asked the question | |

07:43 | , what is the slope of an acceleration time graph | |

07:45 | ? And you don't see jerk or drought ? You | |

07:46 | might have to go of nothing because maybe a t | |

07:49 | shirt didn't cover that topic because for most physics course | |

07:52 | you won't see this . But in the event that | |

07:56 | you do see those terms , that's what it is | |

08:01 | . Now , what about the area of an acceleration | |

08:04 | time graph ? By the way , the units for | |

08:06 | this would be meters per second squared over seconds . | |

08:10 | So it would be meters per second cube . So | |

08:14 | that tells you dealing with the rate of change of | |

08:17 | acceleration . Mhm . By the way the rate of | |

08:20 | change of position is velocity . The rate of change | |

08:23 | of velocity is acceleration and the rate of change of | |

08:26 | acceleration as we just mentioned is jerk or job . | |

08:33 | Now for the area we're multiplying why by X . | |

08:37 | In this case acceleration by time . So what is | |

08:41 | acceleration multiplied by time Acceleration has the units m for | |

08:47 | a 2nd square . If we multiply that by seconds | |

08:50 | we'll get the unit meters over seconds which represents the | |

08:54 | unit for velocity . Yeah . So eight times T | |

08:59 | . Gives you the change in velocity . If he | |

09:03 | replaced Delta V with the final minus the initial you | |

09:08 | get this familiar equation . V final is equal to | |

09:11 | the initial plus 18 . Mhm . So the area | |

09:17 | Mhm . Of an acceleration time graph is the change | |

09:22 | in velocity . Now let's qualify that statement . I | |

09:28 | think so let me changed its craft real quick . | |

09:35 | So let's say we have a curve that looks like | |

09:37 | this let's say that's our position time graph . And | |

09:45 | let's put some numbers let's say this is one , | |

09:47 | This is three and this is five . Yeah . | |

09:54 | Now if we draw the line at three , A | |

09:58 | line that touches the curve at one point . Mhm | |

10:01 | My lines are terrible . Let's do this one more | |

10:03 | time . We'll make the best of that . But | |

10:05 | a line that touches a curve at exactly one and | |

10:09 | that line is known as the tangent line . The | |

10:13 | slope of the tangent line gives you the instantaneous velocity | |

10:18 | . If you're dealing with a position time graphs , | |

10:20 | let me say that one more time , the slope | |

10:23 | of the tangent line of the position . Time graph | |

10:25 | gives you instantaneous velocity . That is the velocity instantly | |

10:30 | , once he is equal to three seconds . Now | |

10:34 | let's say if we have two points at one and | |

10:37 | size and let's draw a line connecting those two points | |

10:44 | . A line that touches the curve at two points | |

10:48 | . That line is a second line , The slope | |

10:50 | of a second line gives you the average velocity . | |

10:54 | The slope of the tangent line gives you instantaneous velocity | |

10:58 | . To calculate the entertainers velocity . That's a little | |

11:00 | difficult because it's hard to find the slope . At | |

11:02 | one point . Now you could use calculus , you | |

11:05 | could find the derivative and that can give you the | |

11:07 | slope of the tangent line , which is the instantaneous | |

11:09 | velocity . The slope of the secret line . You | |

11:13 | could use algebra to get that answer . You could | |

11:16 | use uh Y two over Y one divided by X | |

11:20 | two minus X one . So it's easy to find | |

11:23 | the slope of the second line which is the average | |

11:24 | velocity . Now you can approximate the slope of the | |

11:28 | tangent line using the slope of the second line . | |

11:31 | So if we wanna get a good estimate of the | |

11:33 | slope at exactly t equal stream . If we know | |

11:39 | What the position is at let's say 2.9 and 3.1 | |

11:44 | . We can calculate the slope of the secret line | |

11:48 | Of those two points 2.9 and 3.1 . To approximate | |

11:51 | the slope of the tangent line at three . The | |

11:53 | close to those two points gets a three the more | |

11:56 | accurate the secret line becomes to the slope of the | |

11:59 | tangent line . So as those two points get closer | |

12:03 | and closer to three , the slope of the second | |

12:05 | line approximates the slope of the tangent line . So | |

12:08 | that's how you can find the slope of the tangent | |

12:10 | line using this formula . Mhm . So if you | |

12:13 | were to use values like 2.99 and three points or | |

12:16 | one , it's going to be a very accurate estimate | |

12:19 | of the slope of the tangent line . So let's | |

12:22 | put this all together . When dealing with a position | |

12:24 | time graph . The slope of the tangent line gives | |

12:27 | you the instantaneous velocity . The slope of the secret | |

12:30 | line gives you the average velocity when dealing with an | |

12:35 | acceleration time graph . The area Does't give you the | |

12:39 | instantaneous velocity nor does it give you the average velocity | |

12:42 | , but it gives you the change in velocity . | |

12:45 | That is the final -1 issue . So just make | |

12:48 | sure you see that distinction and remember the slope of | |

12:53 | a position time graph is velocity . The slope of | |

12:56 | velocity . Time graph is acceleration . The slope of | |

13:00 | an acceleration . Time graph is jerk or joke , | |

13:02 | which is not commonly used and the area of the | |

13:06 | velocity time graph is displacement . The area of an | |

13:09 | accelerated time graph is velocity . Those are things you | |

13:12 | have to know if you want to answer questions with | |

13:14 | these time graphs . Now , I'd like to make | |

13:18 | a distinction between two similar time graphs , A position | |

13:27 | time graph and a distance time graph in physics . | |

13:40 | Position time graphs , you'll typically see them as X | |

13:43 | versus T . For a distance time graph , you'll | |

13:46 | see them as diversity . Now , what you need | |

13:50 | to know is that velocity , which I just put | |

13:54 | v velocity is displacement over time . Speed is equal | |

14:05 | to the distance divided by the time . So here | |

14:11 | we're dealing with division . So think of division as | |

14:14 | slope . The slope of a position time graph is | |

14:18 | velocity but the slope of a distance time graph is | |

14:26 | speed . Because remember the slope is D over t | |

14:30 | distance over time which is speed . So that's the | |

14:34 | difference between a distance time graph and the position time | |

14:37 | graph . The position time graph can give you velocity | |

14:41 | if you calculate slope but a distance time graph , | |

14:46 | I mean as I said that correctly position time graph | |

14:48 | can give you the velocity if you calculate the slope | |

14:51 | but the distance time graph can give you the speed | |

14:54 | . If you can't leave the slope . Remember velocity | |

14:56 | is a vector and speed is a scale of quantity | |

15:01 | velocity can be positive or negative but speed is always | |

15:04 | positive . So make sure you see the difference between | |

15:07 | the two . If you're dealing with a position time | |

15:09 | graph versus a distance time graph . Now let's take | |

15:14 | some more notes . So we said that velocity is | |

15:18 | the rate of change of position . Therefore as the | |

15:22 | position increases , the velocity is positive when a position | |

15:27 | is a decrease in velocity is negative . So if | |

15:30 | X is going up that means that the particle or | |

15:33 | the object is moving to the right along the X | |

15:35 | axis . If X is going down , that means | |

15:38 | it's moving to the left . So any time velocity | |

15:41 | is positive . When you're dealing with an ex varsity | |

15:44 | graph , that means the particles moving to the right | |

15:47 | . If losses negative it's moving to the left . | |

15:50 | If the position is constant , that means the velocity | |

15:53 | is zero . Now when the velocity is zero it | |

15:57 | could be that the object is at rest or it | |

16:01 | could be that the object is changing direction . So | |

16:09 | it really depends on the shape of the graph . | |

16:11 | So for instance let's say if you have a position | |

16:14 | time graph that looks like this so notice that it's | |

16:19 | horizontal for quite some time at that moment the particles | |

16:23 | at rest but it could change instantly . Let's say | |

16:28 | if it looks like this well let's do it like | |

16:37 | this actually . So notice that it's horizontal for a | |

16:43 | very brief moment . The tangent line Which is the | |

16:47 | slope at at one The slope of the tangent line | |

16:52 | is zero because the line is horizontal and so at | |

16:56 | that instant it's at rest but it's changing direction . | |

17:01 | So here the position is increasing . That means the | |

17:06 | particles moving to the right because the slope is positive | |

17:10 | , those velocities positive . Here is going down . | |

17:13 | That means the slope is negative which means velocities negative | |

17:17 | . So it's moving to the left . Yeah . | |

17:19 | So it was moving to the right and now it's | |

17:21 | moving to the left . So at the top at | |

17:23 | that peak where the slope is zero it's at rest | |

17:27 | for a very very short time . Or more specifically | |

17:30 | it's changing direction going from right to left . So | |

17:35 | when velocity is zero the particle could be at rest | |

17:39 | or the particle could be a change in direction . | |

17:43 | So keep that in mind . Now we said that | |

17:47 | velocity is the rate of change of position , acceleration | |

17:52 | is the rate of change of velocity . So whenever | |

17:56 | the acceleration is positive , that means that the velocity | |

17:59 | is increasing when the acceleration is negative , the velocity | |

18:04 | is a decrease in . If the acceleration is zero | |

18:08 | , that means that the velocity is constant . Now | |

18:13 | speed is the absolute value of velocity . So if | |

18:18 | the velocity is positive five m/s , that means that | |

18:22 | the speed is positive five . If the velocity is | |

18:26 | negative for meters per second , that means that the | |

18:29 | speed is positive for meters per second . So if | |

18:33 | a particle is moving to the left at four m | |

18:35 | per second , you would say that the speed of | |

18:37 | the particle is simply four m per second , speed | |

18:40 | is always positive . Now we need to talk about | |

18:45 | when an object is speeding up versus when it's slowing | |

18:47 | down , how can you determine when it's speeding up | |

18:55 | and when it's slowing down ? Here's a quick and | |

19:03 | simple way to get the answer . A particle is | |

19:09 | speeding up when the acceleration and velocity have the same | |

19:12 | sign either they're both positive or both negative . In | |

19:19 | this situation the velocity is increasing , it's becoming more | |

19:23 | positive because the acceleration is positive here even though the | |

19:26 | velocities negative , it's becoming more negative . And so | |

19:31 | if you get a larger negative the speed which is | |

19:34 | the absolute value of velocity , that's becoming more positive | |

19:38 | . So in both cases it's speeding up when the | |

19:43 | signs of acceleration and velocity are different Where one is | |

19:46 | positive and the other is negative and that's when the | |

19:50 | particle or the object is slowing down . Yeah . | |

19:54 | Mhm . So let's think about this conceptually here , | |

20:00 | when the acceleration is positive , that means velocities increase | |

20:02 | in velocity is becoming more positive which means speed has | |

20:06 | become more positive , so speed is increasing . Yeah | |

20:10 | , the acceleration here is negative and the velocity is | |

20:13 | negative because the acceleration is negative , the velocity is | |

20:16 | becoming more negative . To think of it has gone | |

20:18 | from negative five to negative Aid . But speed being | |

20:22 | the absolute value of velocity it's going from 5-8 . | |

20:25 | So speed is increasing in that case . Now for | |

20:30 | this situation the velocity is negative but the acceleration is | |

20:33 | positive which means that the velocity is becoming less negative | |

20:37 | . So to illustrate this , let's see if the | |

20:39 | velocity was negative . five , acceleration is making it | |

20:43 | less negative , more positive . So it would become | |

20:46 | like negative too due to a positive acceleration . The | |

20:50 | velocity is increasing when acceleration is positive So -2 is | |

20:55 | higher than -5 on a number line . But if | |

20:57 | you take the absolute value of it You can see | |

20:59 | why the speed is decreasing . Going from 5-2 . | |

21:03 | Ass is going down Now a quick illustration for the | |

21:08 | last one where acceleration is negative but velocity is positive | |

21:13 | , The velocity is becoming less positive . So let's | |

21:16 | say if it was eight With a negative acceleration it | |

21:19 | can go down to four . Speed being the absolute | |

21:23 | value of velocity will be the same , going from | |

21:25 | 8-4 . So the speedily decreasing and us any time | |

21:31 | an object is slowing down , the acceleration and velocity | |

21:35 | have opposite signs when it's speeding up , The acceleration | |

21:39 | and velocity have the same sign . So that's a | |

21:41 | quick and simple way to determine if an object is | |

21:43 | speeding up or if it's slowing down . Now Let's | |

21:47 | focus on the three linear shapes of a position time | |

21:50 | graph . Now these linear shapes exist for any graph | |

21:56 | . So you can have a straight line going up | |

21:58 | , you could have a straight line going in a | |

22:00 | horizontal direction or straight line going down . Those are | |

22:03 | the three linear shapes that you're gonna be dealing with | |

22:07 | now , because these shapes are linear , the slope | |

22:11 | is constant , and for a position time graph flossie | |

22:14 | is a slope . So for these three situations velocity | |

22:21 | is constant and when velocity is constant , what can | |

22:26 | you say about acceleration ? Anytime velocity is constant , | |

22:31 | acceleration is zero , So the acceleration is zero For | |

22:35 | each of these three position time graphs . Now , | |

22:39 | for the first one , the position is increasing any | |

22:42 | time , the position is increased in the velocity is | |

22:45 | positive for the second one , position is not increasing | |

22:49 | its constant , so the velocity is zero , which | |

22:53 | means it could be at rest or it may be | |

22:55 | changing direction . But for this particular shape here it's | |

22:59 | at rest , it's not changing direction , it's not | |

23:02 | going up and then down . But when via zero | |

23:09 | , if you don't have the graph , just know | |

23:10 | that it could be at rest or it could be | |

23:12 | changing direction here , the position is decreasing . Whenever | |

23:17 | the position decreases , the velocity is negative . So | |

23:23 | when dealing with a position time graph , if you | |

23:24 | have these three shapes , just no acceleration is zero | |

23:28 | . If it's going up velocities positive , if it's | |

23:31 | going down velocity is negative . If it's horizontal velocity | |

23:35 | is zero . So in this side it's moving to | |

23:37 | the right , along the X axis here , it's | |

23:40 | movement to the left and for this particular picture , | |

23:44 | Specifically this one , it's at rest . Now let's | |

23:47 | consider the next four fundamental shapes that you'll see with | |

23:51 | a time graph . So now we don't have the | |

23:54 | three linear shapes that we did before , but we | |

23:56 | have four parabolic shapes . So because the position time | |

24:03 | graph is not linear , the velocity is not constant | |

24:06 | . Therefore we have an acceleration . But before you | |

24:10 | go into acceleration , let's talk about velocity . So | |

24:14 | for the first one is the velocity positive or negative | |

24:19 | ? Well , the position is increasing because we're going | |

24:22 | up along the y axis , so therefore velocity is | |

24:27 | positive because the slope is positive here the position function | |

24:31 | is decreasing , so therefore velocity is negative for this | |

24:39 | particular shape , the position function is still decreasing because | |

24:43 | we're going down . So velocity is negative as well | |

24:47 | , but here we are increasing , so X is | |

24:50 | going up . Therefore velocity is positive . So that's | |

24:55 | the velocity for each of those four situations . Now | |

24:58 | , what about acceleration in calculus ? If you've taken | |

25:03 | it before this shape is concave down . This shape | |

25:13 | is known as concave up when dealing with a position | |

25:22 | time graph . If you have a concave down shape | |

25:26 | , the acceleration is negative , so down for negative | |

25:30 | and up for positive . So for now go ahead | |

25:34 | and write that down . So notice that these two | |

25:38 | combined former concave down shape . I put them like | |

25:41 | that together . So you can easily tell that the | |

25:45 | acceleration will be negative . These two shapes combine form | |

25:48 | a concave up shape , this is the first half | |

25:51 | of it , and that's the second half . Yeah | |

25:57 | . Mhm . So for the first two shapes , | |

26:00 | acceleration is negative And for the last two acceleration is | |

26:08 | positive . Now , let's look at this from another | |

26:12 | perspective , we know that the slope tells us the | |

26:17 | velocity , but the way that the slope changes tells | |

26:20 | us the acceleration velocity is the rate of change of | |

26:26 | position , but acceleration is the rate of change of | |

26:29 | velocity . So if we analyze how to slow changes | |

26:32 | , we can get an idea of the acceleration for | |

26:34 | this graph . So at this point The slope appears | |

26:40 | to be approximately one . Mhm . This is a | |

26:43 | slope of one when it rises at a 45° angle | |

26:47 | . When it's horizontal , the slope is zero . | |

26:49 | If it goes down at a 45 degree angle , | |

26:52 | the slope is negative one . Yes . So at | |

26:58 | this point The graph appears to be rising at a | |

27:01 | 45 degree angle . So the slope is approximately one | |

27:04 | here , But then it becomes almost horizontal where the | |

27:08 | slope is approximately zero . So the slope is going | |

27:12 | from 1-0 even though the velocity is positive . Because | |

27:19 | access increasing , we're going up , The slope is | |

27:22 | decreasing , it's going from 1-0 . Therefore we can | |

27:25 | see why the acceleration is negative . Remember the slope | |

27:29 | represents the velocity . So it's a velocity is going | |

27:32 | from 1-0 . It's decelerating . That's why we can | |

27:36 | say the acceleration is negative . So now let's analyze | |

27:40 | the slope for the 2nd 1 . So here it | |

27:43 | appears horizontal And at this point it looks like it's | |

27:46 | going down at a 45° angle . So the slope | |

27:50 | or the velocity is going from 0 to -1 . | |

27:54 | So it's still decreasing , negative one is less than | |

27:57 | zero . So we could see why the acceleration is | |

28:00 | negative . Let me keep these numbers here . Now | |

28:10 | , at this point the slope appears to be negative | |

28:12 | one . It's going down at a 45 degree angle | |

28:15 | , but it's becoming horizontal where the slope is zero | |

28:18 | . So going from negative 1-0 , the slope or | |

28:21 | the velocities increase in . Thus we can see why | |

28:24 | the acceleration is positive and here it's clear to the | |

28:28 | slope appears to be zero and here it's going to | |

28:30 | one . So from 0 to 1 , the velocity | |

28:34 | is increasing , which means the acceleration is positive . | |

28:39 | So any time the acceleration is negative , the velocity | |

28:42 | is decreasing when the acceleration is positive , the velocity | |

28:48 | and the slope is increasing . Yeah . Now the | |

28:51 | last thing that we need to talk about is if | |

28:54 | it's speeding up or slowing down , it's looking at | |

28:57 | the first graph on the left , would you say | |

28:58 | it's speeding up or slowing down ? So if we | |

29:02 | look at the signs for velocity and acceleration , they're | |

29:06 | different . So we can say that it is slowing | |

29:11 | down . Remember speed is the absolute value of velocity | |

29:16 | . If you go from 1-0 , you're slowing down | |

29:20 | here , the signs are the same . So it's | |

29:24 | going to be speeding up this time , velocity is | |

29:27 | zero . Speed being the absolute value of velocity is | |

29:31 | not negative one but positive one . So in this | |

29:34 | case the speed is going from zero , it's a | |

29:36 | plus one . It's speeding up Here , the speed | |

29:39 | is going from 1-0 . So we can see why | |

29:42 | it's slowing down now . For the next case the | |

29:49 | signs are opposite , so therefore it's going to be | |

29:52 | slowing down . Yeah , So if velocity is negative | |

29:56 | one speed is positive one . So going from 1-0 | |

29:59 | , we could see why it's slowing down . And | |

30:03 | for the last case both velocity and acceleration have the | |

30:07 | same sign , so it's going to be speeding up | |

30:13 | These numbers , none of them are negative , so | |

30:15 | speed is gonna be the same , it's gonna be | |

30:17 | 0-1 . And so in that case it's speeding up | |

30:20 | as well . So now you can answer almost every | |

30:24 | question when dealing with position time graphs , you know | |

30:28 | how to determine if the velocity is positive or negative | |

30:31 | if it's increasing or decreasing . Thus , you know | |

30:33 | how to determine the sign of acceleration and whether if | |

30:36 | it's speeding up or slowing down . |

#### DESCRIPTION:

This physics video tutorial provides a basic introduction into motion graphs such as position time graphs, velocity time graphs, and acceleration time graphs. It explains how to use area and slope to calculate the velocity, acceleration, displacement, and whether if the particle is speeding up or slowing down. It also explains how to determine if the velocity is increasing or if the acceleration is positive.

#### OVERVIEW:

Velocity Time Graphs, Acceleration & Position Time Graphs - Physics is a free educational video by The Organic Chemistry Tutor.

This page not only allows students and teachers view Velocity Time Graphs, Acceleration & Position Time Graphs - Physics videos but also find engaging Sample Questions, Apps, Pins, Worksheets, Books related to the following topics.

GRADES:

STANDARDS: