## NotTim 2 years ago I need help understanding diagrams.

1. NotTim

For Example

2. NotTim

|dw:1359418634316:dw|

3. NotTim

so where would the 45 degree angle go i nthe triangle?

4. NotTim

i never did get it right

5. shubhamsrg

|dw:1359448218371:dw|

6. shubhamsrg

This should help ?

7. NotTim

|dw:1359419770094:dw| @shubhamsrg ?

8. shubhamsrg

45 will be special case where all angles be 45 Leme explain you a general case, with angle = x

9. NotTim

say it wasn't 45...

10. shubhamsrg

|dw:1359448684677:dw|

11. shubhamsrg

|dw:1359448743336:dw|

12. Vincent-Lyon.Fr

Hint: Except in geometrical solving of problems, NEVER EVER draw general diagrams with 45° angles. Always draw 20° to 30° angles. It will save you a lot of time.

13. shubhamsrg

|dw:1359448787878:dw|

14. shubhamsrg

|dw:1359448817064:dw|

15. Vincent-Lyon.Fr

|dw:1359448798875:dw|

16. NotTim

|dw:1359420708200:dw| So I know what is going on, then this would be correct also?

17. Vincent-Lyon.Fr

|dw:1359449644111:dw| WHere does this direction point to? If it is horizontal, then you are wrong again. "Your" angle is the other one.

18. NotTim

@Vincent-Lyon.Fr how do you get that?

19. Calculator

just remember when parallel to the slope means: Force produced by the weight-> mgsinx if its perpendicular ( normal ) to the slope, use mgcosx

20. NotTim

the main slope, or the new, smaller slope?

21. Calculator

the original one, below the slope, angle use 45 degrees

22. Calculator

|dw:1359455671403:dw| For x axis : is always sine For y axis : is always cosine

23. NotTim

wait. sorry, so hwo can i derive where the angle will be?

24. tcy

|dw:1359457894005:dw|

25. Calculator

just use this angle for both axis|dw:1359458196671:dw|

26. NotTim

wait...so how do i know the angle for the hypothetical top triangle?

27. Calculator

|dw:1359460336556:dw|

28. NotTim

Ok. To anyone else answering, I will be leaving within 5 minutes. Thamks for all the help guys! At the very least, I know where the angles go, even if I do not knw how to derive it.

29. Calculator

you have to know your trigonometry well and have to look at different angles to solve this problem

30. Calculator

|dw:1359461884908:dw| For the force directed on x axis due to resultant force, F on x = Fcos(30) For the force directed on y axis due to resultant force, F on y = Fsin(30)

31. Calculator

Then,

32. Calculator

|dw:1359462169659:dw|