Introduction to motion - part 3 Video

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Introduction to motion - part 3

Introduction to Motion - Part 3 I am back. So where were we? We were saying, what if we know that velocity or the kind of a change in velocity is acceleration times time and I just wrote more formally and really kind of incorporate the change in velocity, right? The final velocity is equal to the initial velocity plus acceleration times time. Actually, you can have write it like this and I could have written Vf-Vi=acceleration times time and this is the change in velocity, right and actually that’s why I should be doing it as you can tell it like, I going to do some with the stuff how to apply. But I do that for a reason because I want you to get the same intuition that I hopefully have. Instead of just kind of doing it in a very formal way in a book and sometimes the book doesn’t necessarily make the connections on the most natural way. So, this is going straight from my brain to this video and hopefully into your brain. So you know these are all ways of saying the same thing. I actually should write this as you know, change in velocity that the triangle or delta just needs to change. So the final velocity with its initial velocity is equal to acceleration times time. The average velocity, we can just figure out. Now you take the final and you take the initial and you average the two is equal to this and then I said, well, we know what the final velocity is and this is the final velocity. Now the average velocity is this, we substitute it for the final velocity and then we came to this equation for average velocity. Then before I almost run out of time I said I’m going to take this formula for the average velocity and I really encourage you to just play around with this formulas yourself and derive it yourself because it’s going to pay huge rewards later on when you forget the formulas on your exam but you can work it out anyway. So, we have this formula for average velocity and let’s substitute back into this. So, we can say that distance is equal to the average velocity. Well, that is this (Vi+at)/2 times time and we just distribute that t, we have the (Vit+at2)/2. So, distance is equal to the (Vit+at2)/2 and sometimes the physics just teach accelerate (at2)/2 that sometimes people memorize and that’s because a lot of this projectile motion problems. Your Vi=0 especially when you are dropping a rock. So, if your Vi=0 at this term, it would cancel out and if you do that last problem that we just did using this example and you’ll get the same answer where, what did I say? I said we’re accelerating with gravities. So, a=10 meters per second squared and then time is equal to two seconds and then Vi=0. So, the initial velocity is zero so this term just cancels out plus acceleration of ten meters per second squared times time squared. Actually I was going to say not times squared but times squared. Maybe, would someone of you secure another square call the time squared. But anyway, you have ten meters per second squared and that was bad thought but time times squared, time is two seconds. So, it’s four and since we squared the number, we should also square the unit. So, it’s four second squared. All of that over two unlike we learned before well ten times four divided two is twenty. And then we have second squared to the denominator here and we have second square to the numerator here, they cancel out or we just left with meters. Actually I’m going to leave it there for now and then in the next presentation, I’ll explore some of this mechanics even further. I’ll see you soon.

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Introduction to Motion - Part 3

I am back. So where were we? We were saying, what if we know that velocity or the kind of a change in velocity is acceleration times time and I just wrote more formally and really kind of incorporate the change in velocity, right?

The final velocity is equal to the initial velocity plus acceleration times time. Actually, you can have write it like this and I could have written Vf-Vi=acceleration times time and this is the change in velocity, right and actually that’s why I should be doing it as you can tell it like, I going to do some with the stuff how to apply.

But I do that for a reason because I want you to get the same intuition that I hopefully have. Instead of just kind of doing it in a very formal way in a book and sometimes the book doesn’t necessarily make the connections on the most natural way. So, this is going straight from my brain to this video and hopefully into your brain. So you know these are all ways of saying the same thing. I actually should write this as you know, change in velocity that the triangle or delta just needs to change.

So the final velocity with its initial velocity is equal to acceleration times time. The average velocity, we can just figure out. Now you take the final and you take the initial and you average the two is equal to this and then I said, well, we know what the final velocity is and this is the final velocity. Now the average velocity is this, we substitute it for the final velocity and then we came to this equation for average velocity.

Then before I almost run out of time I said I’m going to take this formula for the average velocity and I really encourage you to just play around with this formulas yourself and derive it yourself because it’s going to pay huge rewards later on when you forget the formulas on your exam but you can work it out anyway.

So, we have this formula for average velocity and let’s substitute back into this. So, we can say that distance is equal to the average velocity. Well, that is this (Vi+at)/2 times time and we just distribute that t, we have the (Vit+at2)/2. So, distance is equal to the (Vit+at2)/2 and sometimes the physics just teach accelerate (at2)/2 that sometimes people memorize and that’s because a lot of this projectile motion problems. Your Vi=0 especially when you are dropping a rock. So, if your Vi=0 at this term, it would cancel out and if you do that last problem that we just did using this example and you’ll get the same answer where, what did I say? I said we’re accelerating with gravities. So, a=10 meters per second squared and then time is equal to two seconds and then Vi=0.

So, the initial velocity is zero so this term just cancels out plus acceleration of ten meters per second squared times time squared. Actually I was going to say not times squared but times squared. Maybe, would someone of you secure another square call the time squared. But anyway, you have ten meters per second squared and that was bad thought but time times squared, time is two seconds. So, it’s four and since we squared the number, we should also square the unit. So, it’s four second squared. All of that over two unlike we learned before well ten times four divided two is twenty.

And then we have second squared to the denominator here and we have second square to the numerator here, they cancel out or we just left with meters. Actually I’m going to leave it there for now and then in the next presentation, I’ll explore some of this mechanics even further. I’ll see you soon.

Transcription by: Scribe4you Transcription Services