Suspended object, two rope system

[Nal101]

Homework Statement

1) What is Y-component of the force due to rope 2
2) What is the magnitude of F₂
3) What are the X components of the force due to rope 1 and rope 2

mass = 60kg
\theta = 20 degrees

Homework Equations

F = ma
ma = T-W

The Attempt at a Solution

1) mass * gravity = 60 * -9.8 = -588
To find the Y component, take -588 * sin(90-20) (Should the angle be off of horizontal or vertical, currently set to horizontal)

2) No clue, the actual term 'magnitude' seems to confuse me, so if someone could briefly define what the magnitude of a force is with relevance to the actual force, that would be great.

3) Same as 1, just substitute sin with cos (for rope 2)
For rope 1, is it 0? That doesn't seem right though, because the rope offset the block to create the angle of 20 degrees.

 

[kuruman]

It would be easier to see what is going on if you resolved F₂ into vertical and horizontal components. Then your diagram will look like a cross with four arms at right angles. If the net force is zero on the block, this means that the horizontal and vertical arms are

1. Irrelevant to the problem.
2. Equal in size and opposite in direction, in pairs
3. Don't know.

What do you think?

 

[Nal101]

Obviously, if you assign the entire picture as the system, the net force is going to be zero. What I am trying to figure out is when the system is defined as just the block, and to find the separate external forces as noted in the questions. It's the 'arms' separate force that I need to calculate, knowing the basic rules of equal & opposite (and therefore cancellation) is true, but doesn't help much if at all on the calculations.. other than the fact that on question 3, the numbers should be the same, but one is negative and one is positive.

 

[Furby]

Actually the "equal and opposite forces" is probably the key to solving this problem.

Understanding that the block is currently stationary, then what can you conclude about the net forces on the block?

After breaking F₂ into vertical and horizontal components you can easily observe how those forces interact with F₁ and gravity.

I'm not sure what you're asking about the relativity of magnitude of a force to the actual force. As far as I'm concerned that is nearly the same thing, the only difference being that since force is a vector, an "actual force" would usually be accompanied by a direction, usually an angle. Your question only cares about the magnitude, or the "scalar part". What is that tension in the rope that is keeping the block stationary?

 

[Nal101]

Question: Are my calculations correct? If not, where did I go wrong?

Understanding that the block is currently stationary, then what can you conclude about the net forces on the block?

I already said that they cancel each other out. i.e. the net force acting on the block is zero.

After breaking F2 into vertical and horizontal components you can easily observe how those forces interact with F1 and gravity.

I know, my question is HOW.

 

[kuruman]

...
I know, my question is HOW.

Check this out

http://hyperphysics.phy-astr.gsu.edu/hbase/vect.html