Physics Vector Question.

[Katipwnan]

Aye smart ass *****s in the Mayberry, got a question for you.

If a vector A is 3 m long and vector B is 4 m long. The length of the sum of the vectors must be:
A) 5 m
B) 7 m
C) 12 M
D) some value from 1 m to 7 m

I arrived at the final answer of 5 m by using Pythagoras Theoreom, but the answer was actually d. Does anyone know the reasoning behind that answer?

 

[John Stockton]

it's the last one. If the vectors are in the same exact direction, they add perfectly 3+4 = 7. If they are in opposite directions 4-3 = 1.

 

[Katipwnan]

it's the last one. If the vectors are in the same exact direction, they add perfectly 3+4 = 7. If they are in opposite directions 4-3 = 1.

Hahaha fuck lol. Fuckin brain farted on that. Thanks dude. Question was on my exam and thought it was asking for resultant vector.

 

[JDragon]

Yeah it depends on the direction of the second vector as the length will be the distance between tje starting point of vector 1 and the ending point of vector 2.

 

[thebluerider]

 

[cottagecheesefan]

lmao, why would you use the pythagorean theorem with this?

 

[Kirin]

lmao, why would you use the pythagorean theorem with this?

You can, depending at which angle the vectors are at with respect to one another. That's what makes a vector a vector instead of a scalar.

 

[John Stockton]

lmao, why would you use the pythagorean theorem with this?

He thought it was one vector w/ a value of <3i,4j> and was trying to find the magnitude. Easy mistake to make IMO, especially under the gun during a test.

 

[cottagecheesefan]

He thought it was one vector w/ a value of <3i,4j> and was trying to find the magnitude. Easy mistake to make IMO, especially under the gun during a test.

true, I haven't taken a test in years, thank god.

 

[EvilDDS]

First post nailed it for you.

I came in here to laugh at asking sherdog for help with a physics question but that one wasn't bad at all

 

[Chinballs]

Now the question most sherdoggers wants an answer to: wtf is a vector?

 

[zackryder]

Aye smart ass *****s in the Mayberry, got a question for you.

If a vector A is 3 m long and vector B is 4 m long. The length of the sum of the vectors must be:
A) 5 m
B) 7 m
C) 12 M
D) some value from 1 m to 7 m

I arrived at the final answer of 5 m by using Pythagoras Theoreom, but the answer was actually d. Does anyone know the reasoning behind that answer?

vectors is both magnitude and direction. since ur only given the magnitude and dont know the direction u cant assume anything

if the 2 vectors are in the same direction, you add them (tip to tail)

if the 2 vectors are in opposite direction, you subtract them

 

[TankAbbott4Eva]

That's a clever exam question to confirm the student understands what a vector is to be honest.

 

[Prime Yossarian]

Now the question most sherdoggers wants an answer to: wtf is a vector?

It's a quantity with both magnitude and direction. I always thought that was cool as fuck. When I got really motivated I liked to think of my actions as having magnitude and direction.

 

[Graves The Elder]

you're a vector

 

[cakewalkbaby]

 

[choke you]

Ahhh.......thought this was about cereal.

 

[jmag]

Can you only add two vectors at a time using trig laws? I was doing hw with my kid and we had to add three.

 

[John Stockton]

Can you only add two vectors at a time using trig laws? I was doing hw with my kid and we had to add three.

I'm fuzzy on my calc 3, but I'll try to help. You can either:

A) add the first two vectors and then add that sum to the third one

or

B) If your vectors are already defined on each axis, you can do simple adding of all 3 in one step.

E.g. Let's say you have 3 vectors: <1,2>, <3,-1>, and <4,0>

You could do this simple operation: <1,2> + <3,-1> + <4,0> = <8,1>

I'm not sure if I explained that very well, so let me know. I can also show you how to get these axis values if you already know the magnitude and angle of the vector.

 

[jmag]

I'm fuzzy on my calc 3, but I'll try to help. You can either:

A) add the first two vectors and then add that sum to the third one

or

B) If your vectors are already defined on each axis, you can do simple adding of all 3 in one step.

E.g. Let's say you have 3 vectors: <1,2>, <3,-1>, and <4,0>

You could do this simple operation: <1,2> + <3,-1> + <4,0> = <8,1>

I'm not sure if I explained that very well, so let me know. I can also show you how to get these axis values if you already know the magnitude and angle of the vector.

We had magnitudes and angles, so added two using law of cosines or whichever I don't remember, then added the resultant to the third and got it right, but I was wondering if we could add more than two that way at a time.