# Pulley system in equilibrium

1. Oct 7, 2007

### anglum

The problem involves a picture so i posted it so it can be seen and easier or you guys to help me

i know that the total sum of the tensions in this need to equal 37.4N + 61.4N

but i get confused when angles get brought into play

http://i199.photobucket.com/albums/aa314/anglum/help.jpg

2. Oct 7, 2007

### Staff: Mentor

Examine the first "knot". What must be true about the forces acting on that knot? Hint: Consider vertical and horizontal components separately.

3. Oct 7, 2007

### anglum

i am so lost on this problem... would the forces actin on the first knot need to equal 37.4N???

4. Oct 7, 2007

### Staff: Mentor

Since the system is in equilibrium, the total force must be zero.

5. Oct 7, 2007

### anglum

ok so if the total force on the first knot is 0 then i can assume that

37.4N + T1+T2 = 0??

6. Oct 7, 2007

### anglum

i also need to find the other angles value in degrees as a part 4 of the question

7. Oct 7, 2007

### Staff: Mentor

No, since forces are vectors and must be added as vectors. As I said earlier: Consider vertical and horizontal components separately.

8. Oct 7, 2007

### anglum

i am totally lost right now... i dont see y the forces of t1 t2 and the weight dont equal to zero

9. Oct 7, 2007

### anglum

the vertical componentei s37.4 and the horizontal is t2 ????

10. Oct 7, 2007

### Staff: Mentor

The vectors add to zero, but not just the numbers.

For each of those three forces list the following:
(1) x-component
(2) y-component

Some of the components will be zero.

11. Oct 7, 2007

### anglum

ok for the wegith hangin down the x component is 0 and the y component is 37.4N

for T2 the horizontal is WHAT while the vertical is 0

and for T1 the vertical is sin41 = T1/X

and for T1 the horizontal is cos 41 = T1/X

12. Oct 7, 2007

### anglum

ahhhh i figured out the first 3 parts

im stuck on the angle

13. Oct 7, 2007

### Staff: Mentor

Since it's downward, call it -37.4 N.

Call the horizontal component T2.

The vertical component is T1 sin41.
The horizontal component is -T1 cos41.

Now add up the vertical components and set to zero. Do the same for the horizontal components.