Video Gallery

CH 3 part 1 Accelerated Motion

Go to Video Gallery Added Aug 29, 2018 •

Copy this URL:
Embed code:	<iframe class="edlio-embed-player" type="text/html" width="640" height="360" src="//www.curiehs.org/apps/embed/?v=190311" frameborder="0" allowfullscreen></iframe> Change dimensions

Go HD

Show Transcript

so now I'm topic 2.2 we're going to look at accelerated motion and accelerated motion is essentially refers to any kind of change of velocity but the technical definition of it is the rate of change of velocity by rate of change of nasty I mean specifically the change of velocity with respect to time that's a vector quantity and we can Define it through a formula Smalley which is the symbol for acceleration is equal to the change in velocity over the change in time and we also might break that change in velocity down so often times will drop the vector sum I want to Simply use the labels and will say that V - be not divided by the time change so we might as me not represents the change in velocity divided that by the amount of time and they took to take that to make that change Bastian you get the acceleration velocity is a vector quantity that means it has both Direction and magnitude and important thing to notice there is actually two types of acceleration and the two times acceleration are result of the the property of a vector quality of velocity that is the same velocity has both magnitude and direction if either of those change then you will experience acceleration for the purposes of this topic we're going to focus entirely on the magnitude and then a subsequent topic will look at the aspect of changing the direction of that in the sort of special type of acceleration that that leads to just as we saw with the velocity formula this formula is for the average acceleration if however we want to turn that into a to instantaneous properties and the purpose for turning it into instantaneous acceleration would be to be able to calculate the final velocity the initial velocity the time or obviously even Excel in order to be able to make that sort of calculation and find useful information from that we need the instantaneous acceleration will just like with the velocity there's or two as one is by looking at the velocity change over an infant assembly small time this will provide the instantaneous acceleration but it was an approximation of the instantaneous acceleration and if we make the time change very very small then that means they will be getting very very close to the instantaneous value of the acceleration and therefore even though it's in a animation it's a good approximation you did basically gives us the value of the acceleration and even better way to do it though is to not have the acceleration change if we maintain a constant acceleration throughout the entire motion then acceleration will turn this formula for average acceleration into the formula for instantaneous acceleration and then it becomes much more useful because we can calculate or solve for any one of the four properties really important to notice that there are four variables in any one of those can be solved for it's not just a formula for acceleration in other words it's a formula for acceleration formula for velocity formula for initial velocity or formula for time depending on which of the four variables that we're looking for the result of that let's take a look at this equation and look at it in a form that is almost even more common than the definition so we'll start with minus V not over t and what I want to do is to solve for V the final velocity often times during accelerated motion we would like to know the based on the initial velocity and the time in the acceleration what will be our velocity at the end of the motion so let me just make a couple of steps I'm going to x t to give me 80 is equal to V - V not allowed to be not to the other side to get 80 must be nice and so this is a very useful version of the form this is a little weird way of looking at it though so let me go ahead and put it in our final form if you look close to the formula you can see that there are essentially two variables because remember this is a situation in which we're going to use this equation for constant or uniform acceleration that means the egg Envy equals 80 plus b not is a constant and unchanging property also once the motion starts obviously the initial velocity will not change that now also becomes a fixed quantity so with this being a fixed quantity and that being a Quality Health did you recognize that this is the equation of a line the variable that I would plot on the vertical axis would be the velocity and I would plot that versus the time and what I would find is 4 inch outside forecast in a uniform duration this thing is going to produce a line so let me make a note of that this is the equation of a line and let me just remind you the equation of a line is y equals m must be okay so what's your take a look at one quick example and then we'll move on to some variations of the acceleration equations so when our first example we're going to take a look at Sarah I was jogging at 2.5 meters per second when she begins to accelerate at 1.5 meters per second squared so it's important to notice the units for acceleration we slide back down here I'm going to change in velocity while the change in velocity is meters per ride by meters per second by seconds then I end up with meters per second squared and she's going to accelerate at that rate of 1.5 meters per second squared for 4 seconds and the obvious question is what is your plan of LA sleep with any problem the most important thing is to pull out what is given to you so we can take it from being a word problem to being more of an algebra problem so I'm just going to go in order of the things that were given to me first I was given the knot and that was a positive 2.5 meters per second I was given the acceleration 1.5 meters per second squared and I was given the time that was 4.0 seconds and I'm looking for the final velocity I would expect when I look at your solution to problems that the particular now is we need to more complicated problems but I'm going to see this list of given information the next step is I'm going to see the and that you're going to use to solve this in this case the equation is very easy because it's already solved for the variable that I'm looking for it however it was not solve for the variable that I was looking for what I would expect from you is solve for the variable first then go and plug in your giving information and go ahead and then go to the calculator and plug things in but in this case it's already done for us so we're going to plug in the acceleration of 1.5 I'm 4.0 and will add that to the original 2.5 that we started with so in this case 1.5 * 4.0 will give me 6.0 what's the original 2.52 especially multiplying a x t is going to give me his it's going to tell me how much the velocity increase by every one second of motion I will increase my speed by 1.5 meters per second for every second that I move or Sarah Holmes I should say the velocity will increase by 1.5 meters per second so for 4 seconds that will give me six meters per second increase and my final answer then since I was already more she was already moving at .5 then I'll end up with 8.5 meters per second and that's my final answer

Video Gallery

CH 3 part 1 Accelerated Motion

Popular Videos