Pretty dificult to explain I have a 60 degree angle with 100N going to the right and 80N going diagonal (up,right) how do I find the magnitude of the resultant force ? Please help me!

The easiest way is usually to break each force up into its individual horizontal and vertical components. Then you can add like components together.

In your case, the horizontal force of 100N is trivial since it doesn't have any vertical component. You can simply write it as

,

where and are unit vectors in the x- and y-direction, respectively.

The second force, 80N at an angle of 60 degrees, is more typical with both x- and y-components:

.

Now you can just add the x-components and y-components together to get the resultant vector:

.

Finally, to find the magnitude of the resultant, you can just use the distance formula (a.k.a. the Pythagorean theorem). Since the x- and y-components of the resultant form the legs of a right triangle, the magnitude of the resultant is simply the length of the hypotenuse of that triangle.



And for future reference, remember sohcahtoa? Tangent = opposite over adjacent? If you want to find the angle of the resultant vector, again consider that the x- and y-components form a right triangle where the resultant is the hypotenuse. The tangent of the angle is equal to the y-component divided by the x-component. Thus



Does that make sense?

Yes that makes sense :) I just don't understand why the y axis is is 40 /¬3 (dont know how to put the square root sign) thanks a lot for your help !

Sorry, I skipped over a step there. It's from fundamental trigonometry. If you remember:



and



Hence, the coefficients are and

I hope that helps.

If u want help in da imagining part of how exactly forces add vectorically, simply imagine a game of snooke. Imagine one ball being hit from as many as side as da number of forces... and den try to predict da trajectory based on trial and error...

For avoiding da hard mathematics employed above...
Try to use triangle law of vector addition.(very simple)
.
.. google around for that law

The triangle law simply states that two vectors are added head to toe. No kidding. Good luck answering the OP's question armed with only THAT knowledge.

Ldog, chat speak is against the rules of this site. If English isn't your first language (I'm assuming it's not based on your posts), then please, at least type using full words.

For instance;

da = the
u = you
den = then

Your other posts are even worse, and will be reported if this continues.

There's not space limit, there's no charge per letter, so use the best English you're capable of, using actual words.

Thanks. :)

Gotcha,
So you are least interested in the material of the answer ,and rather on how it is answered...
I see.
(notice: my english is better here)
:)
No offence.
I will see to it.
And your assumption is pretty wrong.there
But you made me interested in what made you assume so??

Would you mind , being a little clearer... what exactly is OP?.
And believe me, triangle law of vector addition is more then enough for vector summation.


PS: I hope you remember that parallel shifting of vectors causes no change to the initial problem... :)

No, the quality of an answer concerns BOTH the content and the presentation of it. What's the point of having a good answer if it's all complicated and causes more confusion than good? As such, chat language is not very well accepted on here.

'Worse' refers to the presentation your used. And this is not an assumption, this is a fact.

OP = Original Post(er)

If you use this, you'll have to know the cosine and sine rules, without which, the breaking down of components are much easier.

Yes, I certainly understand that. And I agree, the most straightforward way to add vectors is by applying the triangle law. It's what we've all done since we first learned about vectors in our first baby physics classes. You start with one vector, then you parallel shift the other so that it's tail lines up with the first vector's head. The resultant is the vector from the first tail to the last head. It's not exactly rocket science. :)

So yes, it would be very easy to sketch the problem the OP (original poster) was talking about and use the triangle law to sketch the resultant. However, the question wasn't just to draw it or point to it and say "Here it is!"; it was to find its magnitude (in the mathematical sense, which means to find it exactly, not estimate it). The only way you're going to be able to do that is to apply trigonometry. (Okay, maybe not the only way, but certainly by far the simplest way :) ). If you disagree and can demonstrate an easier way using only the triangle law, please show us! I'm always glad to learn other ways to approach problems, especially if the ways are simpler than what I already know.

By the way, please don't be discouraged by our criticism about your "chat speak" in your first posts. We're just explaining the rules, and you were very polite to abide by them as soon as you were told. I don't know if I've seen all of your posts, but I've seen several in various science categories, and although the ones I saw didn't elaborate very much, they certainly weren't wrong. I'm sure you have plenty of useful knowledge to contribute here. Thanks for posting.