Unit 3 and Vectors

So whoever actually looks at the pictures on my blog must think I'm animal-obsessed by now. For those who care to read this, I am not, but my dogs are the easiest things to capture in motion. Anyway, this is my dog being chased.  This picture shows relative magnitude and the direction he is running. Luke is running fast enough to blur the picture. You can tell this because he is blurry. He is also running in the direction of the camera; you can tell this because his head seems larger way than the rest of his body in this picture.

This represents a vector, which shows magnitude (muchness) and direction.

(And the picture refuses to let itself be fixed. I tried.)

Velocity and Time

At the top of a building, two identical objects are released. Object A is thrown downwards, while Object B is simply dropped. Which of the two has gained more velocity? 

(Hint: Which object takes longer to reach the ground?)

This is similar to one of the questions on the practice quiz for Mr. Blake's class.

Answer: Object B gains more velocity. The longer an object takes to reach its destination, the more velocity it gains. 

It took me a while to understand this, actually. I ended up asking my genius physics friend, Robert. He explained the concept to me. While I didn't remember all of what he said, I do remember that he brought up the equation V = Vo + AT. As you can see, acceleration is multiplied by time. I think Robert said that because the equation works like that, the higher time is, the higher velocity will be.

longer time = more velocity

(And I admit that this picture has nothing to do with this blog post.)

What Goes Up...

...must come down. And when it is caught at the same level, it will have the same speed as when it was thrown up, but in the opposite direction. The progression of speed will be as follows: fast-slower-slow-stop-slow-faster-fast. Does that make sense?

As an example, I will use the rose here in my picture (because I was too lazy to take another picture). If I throw the rose up at a speed of 2 m/s and catch it at the same height, the speed will still be 2 m/s, but the direction will be different. The rose would be going 2 m/s downwards instead of upwards.

Kinematics x Doggy

Velocity is similar to speed in that they both deal with how fast something is moving; however, velocity also deals with the direction in which the thing is moving. Therefore, an object can be changing its velocity, but not its speed. For example, when my dog, pictured here, runs at a constant pace around my yard, his speed will not change. However, because my dog has to turn around and run in giant circles to avoid hitting my gates and walls, he changes his direction and therefore changes his velocity as well. In essence, direction is the only difference between speed and velocity.