yego.me
💡 Stop wasting time. Read Youtube instead of watch. Download Chrome Extension

Interpreting statements about vectors | Vectors | Precalculus | Khan Academy


2m read
·Nov 10, 2024

We're told that particles A and B are moving along a plane. Their velocities are represented by the vectors vector A and vector B respectively. Which option best describes the meaning of the following statement? Choose one answer.

So pause this video and try to work through this on your own before we work through this together.

All right, now let's work through this together. So this is saying that the magnitude of vector A is equal to the magnitude of vector B.

So we know that a vector is specified by both a magnitude and a direction, and this is just saying that the magnitudes are the same.

For example, vector A could look like this, and vector B could look like this. It could do something like that, where it has the same magnitude and the same direction, or vector B might be in a completely different direction. The magnitudes being equivalent just tells us that the length of these arrows are the same, but we could have different directions here.

So what this tells me is that we have the same speed, which is the magnitude of velocity, but not necessarily the same direction.

Now let's look at the choices here. The first choice is: the two particles move at the same speed and in the same direction. So we've already said that that's not necessarily the case. In order for choice A to be correct, they would essentially have to be equivalent vectors.

Choice A would be the case if we said that vector A is equal to vector B. Then they would have to have the same magnitude and the same direction, the same magnitude and the same direction. But that's not what they told us. They just told us that the magnitudes are the same, not necessarily the directions. So I'll rule that one out.

The two particles move at the same speed but not necessarily in the same direction. Yes, that's what we just talked about. They have the same speed, which is the magnitude of velocity, but they didn't tell us anything about the direction, just the magnitudes. So I like this choice.

But let's look at choice C. The two particles move in the same direction but not necessarily at the same speed. Well, we know they move at the same speed; that's what this is telling us. The magnitudes are the same. We just don't know anything about the direction.

So I would rule this one out as well. In order for choice C to be the case, you would see something like this: maybe that is vector A right here, and then vector B would move in the same direction, but it would have a different magnitude. And here you would visualize the magnitude as the length of the arrow. But that's not what they told us; they told us this right over there.

More Articles

View All
Psychology of money part 2 | Financial goals | Financial Literacy | Khan Academy
So let’s talk about a few more biases that might creep in when we start thinking about money. One is an anchor bias. Now, an anchor bias is where if initially you think something is worth more, say, and then all of a sudden you find out that it costs less…
The Stock Market Is About To Go Wild | DO THIS NOW
What’s Graham up? It’s guys you hear. So today, we will attempt to answer one of the oldest and most elusive questions in the entire universe: why the stock market is about to go absolutely insane throughout these next few months. With some of the bigges…
Limits of composite functions: external limit doesn't exist | AP Calculus | Khan Academy
So, over here I have two functions that have been visually or graphically defined. On the left here, I have the graph of g of x, and on the right here, I have the graph of h of x. What I want to do is figure out what is the limit of g of h of x as x appro…
Life's Biggest Mysteries
Consciousness, it’s our awareness, our understanding, our ignorance, our daily. Consciousness leaves out more than it takes in, and due to this, it leaves out important things; things that would help relieve us if we knew them. If we had a higher awarenes…
Modeling with multiple variables: Pancakes | Modeling | Algebra || | Khan Academy
We are told that Jade is making pancakes using flour, eggs, and milk. This table gives the cost per kilogram of each ingredient and the amount in kilograms that Jade uses. All right, the total amount Jade spends on ingredients is six dollars. Write an eq…
Ray Dalio: Are we in a Stock Market Bubble?
So Ray Dalio is back on YouTube and his most recent video is actually a really cool 10 minute explainer on whether we’re currently in a stock market bubble. Now Ray is obviously the founder of Bridgewater Associates, the most successful hedge fund the wor…