English School for Non-Native-English-Speakers

[Ben]

Topic 3:

Speed vs. Velocity:

Speed is just a general reference to how fast something/someone is moving/working, etc. For example, you can measure the speed at which you are running.

Velocity is the rate at what an object/person is moving. For example, if you are in a car, and you just keep driving forward, reverse, and dive back to your original spot, your velocity is zero, because you are not actually going anywhere.

[Krom]

Correct me if I'm wrong, Velocity is a rate of gaining or loosing the speed. For example free-fall velocity in vacuum onto Earth is ~9.8m/s.

[Ben]

Yeah, that would be velocity
My example was not good. Yours is much better.

[Lewin]

No that's wrong. Velocity is the rate of change of your position, e.g. 5 m/s north. Acceleration is change in velocity, e.g. 9.8 m/s^2. Speed is velocity without a direction, e.g. 5 m/s. That's the only difference between velocity and speed, velocity has the direction as well. It's like the difference between position and distance. Position has a direction relative to the origin, distance does not.

[Ben]

Your definition is right, but an object free falling does have a speed and direction, yes?

Although Krom wasn't actually stating anything about an object free falling, so...

[Lewin]

Your definition is right, but an object free falling does have a speed and direction, yes?

Yes, and another word for that speed and direction would be velocity (it has both speed and direction)

Correct me if I'm wrong, Velocity is a rate of gaining or loosing the speed. For example free-fall velocity in vacuum onto Earth is ~9.8m/s.

The acceleration of an object free falling towards earth at sea level is 9.8 m/s^2. The velocity/speed will be continuously getting faster and faster (after 1 second it will be 9.8 m/s, after 2 seconds it will be 19.6 m/s... etc.). The direction component of the velocity will be constant (towards the earth), only the magnitude component will be increasing.

Acceleration is the rate of gaining or losing velocity (or speed, depending on whether you care about the direction)

[Ben]

The acceleration of an object free falling towards earth at sea level is 9.8 m/s^2. The velocity/speed will be continuously getting faster and faster (after 1 second it will be 9.8 m/s, after 2 seconds it will be 19.6 m/s... etc.). The direction component of the velocity will be constant (towards the earth), only the magnitude component will be increasing.

Ahhh, good point (direction remains the same: towards the ground). You've corrected me, and I am abased.

[Krom]

My bad, rate of gaining or loosing the speed is indeed an acceleration (deceleration).

Speed - actual moving speed along the twysted road
Velocity - speed towards the target
Acceleration - change in speed

?

[Ben]

Yeah, except maybe, like Lewin said, a little more precise on the velocity: speed and rate towards the target.

I can't give an example now, because I'm terribly tired and I don't want to make another dumb mistake today. What I need is some good sleep

[Krom]

Problem is that in Russian there's no simple equivalent word for velocity

[ChrisEggII]

Can anyone explain for me about transliteration from Cyrillic? Last time I played with Ukrainian guy and I tried polish transliteration. He didn't understand anything, so we had to speak English.

[pawel95]

Example: "BludMaster is more drunk than Revolution."

Excellent example Ben

[Ben]

Thanks pawel! I've been putting subliminal messages in this topic, hiding little inside jokes/ things only a few select would understand. I'm wondering how many people have picked up on those?

It has been awhile since the teacher gave a lesson, too!

[Bence791]

English school for English-Native-Speakers!
http://www.twitch.tv/sado0000001/b/444199831
(watch from 0:06:15) yay

[Ben]

Spelling is not my forte.