## YumYum247 one year ago Yelp me please!!!!

1. YumYum247

2. YumYum247

I've already done the question but can someone please check it for me!!! ?!?!?! d_p

3. YumYum247

4. YumYum247

5. YumYum247

can you zoo in on it?!?!?!?!

6. YumYum247

7. johnweldon1993

Just 1 sec finishing up a previous post :)

8. johnweldon1993

Okay back sorry about that...let me take a look

9. YumYum247

can you see my answer key?!?!?!?!?!?!

10. johnweldon1993

It didnt load at first for some reason but yeah I got it

11. johnweldon1993

So everything looks perfect...did you just want confirmation or did this turn out incorrect?

12. YumYum247

no just for confirmation but can you help me with net force?!?!?!?! ?

13. YumYum247

i know that the net force is 24N but at what angle tho?!?!?!

14. johnweldon1993

Oh okay... well to make your life SO much easier I'm going to show you a quicker easier way to do this question And it will answer the angle question as well :)

15. YumYum247

Thank you!!! :")

16. YumYum247

i think i'm looking for the resultant angle between "C" and "A"....i think...

17. johnweldon1993

Net force of these 2 forces |dw:1442876451291:dw| If we figure out the components of these vectors...we can add them and find the resultant that way...since we know $$\large \text{Resultant} = \sqrt{F_x^2 + F_y^2}$$ So...we know that the Force and the COSINE of the angle, give us our 'x' components for the vectors... And the Force and the SINE of the angle give us the 'y' components *Let the 12N force be V1 and 15N be V2 and let us break them into components $\large V_1 = <12cos(32), 12sin(32)>$ $\large V_2 = <15cos(24), 15sin(24)>$ Summing the components of the 2 Give us $\large \text{Resultant} = <12cos(32) + 15cos(24), 12sin(32) + 15sin(24)> \\ = <23.87976, 0.25798>$ And the magnitude of the resultant is our Resultant vector $\large V = \sqrt{23.87976^2 + 0.25798^2} = 23.88N$

18. YumYum247

yes i get about the same amount of force.....

19. johnweldon1993

Now I'm not sure if you've seen the whole breaking vectors into components...but it is very easy as you can see...and quick! And 1 good thing about it is....you see how we found our resultant to be $\large V = <23.87976, 0.25798>$ Well...those are the COMPONENTS of the vector SO, a neat little trick is...to find the angle this vector is pointing...we simply take the 'y' components....divide it by the 'x' component...and take the inverse tangent of that answer So $\large tan^{-1}\theta = \frac{y}{x}$ $\large \theta = tan^{-1} (\frac{0.25798}{23.87976}) = ??$

20. YumYum247

but the thing is that all the angles are given.....so what are we looking for?!?!?!?!

21. johnweldon1993

|dw:1442877340365:dw|

22. johnweldon1993

We are to find that "single force" and that "SOME angle"

23. johnweldon1993

We already found the force...now we need to find what angle it is being applied at

24. YumYum247

with respect to what?

25. johnweldon1993

With respect to the horizontal

26. YumYum247

ok so am i using the same varialbes i used previously to find hte net force....A and C?

27. johnweldon1993

Nope those are out of the question now because we replaced those 2 forces with this single force We are just using the components of the vector we found like I wrote above

28. YumYum247

ok

29. johnweldon1993

I fell like this isnt making sense... So we have 2 forces acting on something By adding those 2...we found a "resultant" force that we can replace those 2 forces with i.e....it wouldnt matter if we used those 2 forces acting at those different angles....or used this 1 new vector acting at some angle....the box would feel the same exact force

30. johnweldon1993

So instead of having 2 forces of 12N acting at 32 degrees above the horizontal....and 15N acting at 24 degrees below the horizontal We instead us just 1 force of 23.88N acting at SOME angle with respect to the horizontal

31. johnweldon1993

And that SOME angle....is solved using that formula I wrote above $\large \text{Angle} = \tan^{-1}(\frac{0.25798}{23.87976}) = ?$

32. YumYum247

ok thank you very much.....it's too noisey here....:"D i can't focus.

33. YumYum247

but i think i got it.....!!! :D

34. YumYum247

i'm getting 0.61 deg....that's not even a one complete degree....

35. YumYum247

i don't want to use the component method.... x comp and y comp, please just tell me from what i've done, how do i go about find the angle....Please help :")