So anyways, once we multiple we get now two times 250 is 500. There's no shifting business, okay? All right. It's not that the two got shifted up, this is how it works. Now that I've multiplied this two and two, it's canceled. It's in the denominator, I will multiply by two on the right side and also multiply by two on the left side. Two in the denominator, I have to shift this up to the left. Now, you know earlier what I should do? I should think that, you know, to get rid of this say So again, if you've not done this before, good idea to pause the video and see if you can do this Algebra and figure out what T is. And now, to calculate T square, we just have to do some Algebra. I usually like to put in the units so that we will get theĪnswer with the units.
T plus half A T square and see what T is. What's the point? And so we have a winner! We can use S equal to U So this is useless for us, right? Because there is no T. The third equationĭoesn't even have T in it. So, you know what? We can go ahead and use this equation. We have T in it, so that's good because we want to calculate T.
We're not given that number, and so because V's also not given, we can't use that equation. The velocity over here and that's not mentioned to us. So we can use thatĮquation to calculate T. If you look at the firstĮquation, there's a T in it. Which of these equations you choose to figure out what T is. So, can you try this one yourself first? Go ahead, give it a shot! Pause the video and see List and think about which equation to choose So now, given these three things, we can go to our equation And I think that's about it, right? That's all that's given. Okay, what else do we know? We know that displacement S. Speed is increasing, it's a positive five. When the speed is decreasing we will say the acceleration is negative. Whenever the speed is increasing, we say it's positive and The only thing to be carefulĪbout the acceleration is it can be both positive and negative. We know that in this entire stretch the cheetah starts from rest. Which of these variables are given to us and then we will see which equation we can So, you know what we'll do? We'll just think about But these three equations will work whenever our objects are going at constant acceleration. So, you know what? It will be a good idea to goīack and watch that video. With these equations then we have talked a lot about them. Then we have three equations of motion where V is the final velocity. Is a constant uniform, whenever the acceleration does not change, it's the same over the entire stretch. And you've seen before, whenever the acceleration So, what to do? How do I calculate the time? Well, we're in luck because we're talking aboutĪcceleration uniformly. But if the speed is changing, well, we can't use this formula. If this speed is a constant, then you can put some number here. This number is changing what number would you put over here to calculate distance and time? You can't, right? So this formula is only useful In this case the speed is increasing because the cheetah is accelerating. But notice in our example the speed is continuously changing. Is because this is only useful if speed was a constant. So, can I use this toĬalculate time is the question. That comes to my mind when you're talking about How much time? Now, my initial thoughts would be can I just go ahead and use the formula speed equals distance over time? This is the first thing So, how long does our cheetah take to go from here to here? That is the question.
We need to calculate the time it takes to cover this distance. A little later it would haveĬome somewhere over here and now it's a little fast.
Maybe, and it speeds up and so its acceleration is given to us as five meters per second squared. And accelerates uniformly atįive meters per second squared. So let's say this is ourĬheetah initially at rest. And it's given that theĬheetah starts from rest. And you know what? It always help to drawĪ diagram, so let's see. So, let's think about what's given to us. A cheetah starts from restĪnd accelerates uniformly at five meters per second Just by using our intuition, we can begin to see how rotational quantities like\boldsymbolbecause the unknown is already on one side and all other terms are known.- Let's solve two problems on accelerated motion.