Main content

## Algebra (all content)

### Course: Algebra (all content) > Unit 19

Lesson 1: Vector basics# Recognizing vectors practice

Try two questions that make sure you understand that vectors have magnitude and direction.

## Problem 1

## Problem 2

## Want to join the conversation?

- i don't understand whether the time is a scalar or vectoral magnitude. if we can say it is vectoral, why do we get a scalar magnitude when we divide the distance (not displacement) by the time?(16 votes)
- You are seeing time according to classical physics. If we see time according to the theory of relativity time is vector whose direction is towards future.(6 votes)

- Is Force a scalar or a vector quantity ?(8 votes)
- I think Force should be a vector, since it possess both a scalar and a direction.(11 votes)

- The answer choices in problem one confuse me. Why isn't the length of the distance between the points (0,0) and (2,7) considered a vector? Is it required to be a line of some sort in order to be a vector?(4 votes)
- Vectors need both a magnitude (distance) and direction.

If you just know the length, you have the magnitude but no direction. The answer options 2 and 4 tell you where to start from, so they give both the distance and direction.

Hope this helps.(10 votes)

- is there a tip or something that can help you know about if its a vector or not(4 votes)
- The definition of a vector contains tips. If it has a
**direction**AND**magnitude/ size**, then it is a VECTOR.(9 votes)

- Why is electric current scalar when it has a direction?(3 votes)
- This might be complicated for you
**IF**you have not yet learnt vector laws. But anyway, there is a law called the Parallelogram Law Of Vectors . If a quantity obeys this rule and the other rules for vectors, it will be considered a vector quantity. But electric current was tested and it did not obey this rule. So, even if it had a magnitude and direction, it was not considered a vector.(5 votes)

- How can the movement of an aeroplane be considered as a vector?(2 votes)
- The movement of an airplane can be considered a vector, because an airplane always has a speed (or magnitude) and has a movement (or direction). Technically all real world movements can be considered a vector, because a force is always applied (the magnitude {2N for example}) and movement always results in a change of location (which is always in a direction {the left for example})(3 votes)

- why isn't the length of the distance between the black ball and white ball a vector. the length is from the black ball to the white ball and the direction is from the black ball to the white ball.(3 votes)
- length is not a vector, length is just a distance. if you add the information of the direction it is no longer just length. In the case of the two points it is then the line segment, but more generally you could think of it as displacement(1 vote)

- How do Vectors apply in pre-cal?(1 vote)
- They are used to describe a whole host of physical phenomena from wind speed to airplane velocity/acceleration to friction on a wheel to forces acting on a bridge. Vectors are EVERYWHERE(3 votes)

- Does the starting point have to be given (it's location, like 1, 2 on a grid) for it to be a vector?(1 vote)
- Yes. This is because the starting point automatically gives the direction of the vector. For example, like you said, let's say the starting point is (1,2). But in order to have a vector, you also need an ending point, which depends on the direction of vector. Now let's say that the ending point is (4,7). The magnitude of the example vector is the square root of 3^2+4^2= 5, according to the Distance Formula, and the direction is Northeast. If I haven't told you that one of them is the starting point, then there would be two possible directions of the line segment. That's why starting points of a vector are always given. Hope this helps :D(2 votes)

- how do i find the angle measures of a vector(1 vote)
- The angle measure of a vector can be found whit the equation TanѲ=y/x. Where Ѳ=angle, y=the change in y of the vector (y1-y2 where y1 is the y coordinate of the start of the vector and y2 is the y coordinate of the end of the vector), and x= the change in x of the vector (x1-x2 where x1 is the x coordinate of the start of the vector and x2 is the x coordinate of the end of the vector). That's assuming that the answer is in rectangular form (0,0; 1,1 or 1i+1j). You can also use the formulas vx=||v||cosѲ, (where vx= the change in x of the vector, ||v||= the magnitude of the vector, and Ѳ= the angle) or vy=||v||sinѲ, (where vy= the change in y of the vector, ||v||= the magnitude of the vector, and Ѳ= the angle)(2 votes)