Quick question about resolving force

[kougou]

[URgent!] quick question about resolving force

Homework Statement

Hello guys...

I have trouble resolving force into its y- components. Dont laugh. Please have a look on the photo I attached. The force is perpendicular to the slop, and the angle of the slope is given there. And then, what I did is just dot(extend the force), and then use sin(angle) to resolve the force into its component. Of course this is not right, so, why this is wrong. why?

Homework Equations

http://img860.imageshack.us/img860/513/xisu.png

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The Attempt at a Solution

 

[PhanthomJay]

You are incorrectly calculating the force components...the force acts at what angle to the horizontal? (Use geometry). Then find the y component of the force using trig.

 

[kougou]

no, why is this incorrect? where did I mess up?

 

[kougou]

You are incorrectly calculating the force components...the force acts at what angle to the horizontal? (Use geometry). Then find the y component of the force using trig.

where did i mess up? horizontal is 36 degree, and cos 36 will give x, and sin 36 will give y. but why this is not right?

 

[berkeman]

Homework Statement

Hello guys...

I have trouble resolving force into its y- components. Dont laugh. Please have a look on the photo I attached. The force is perpendicular to the slop, and the angle of the slope is given there. And then, what I did is just dot(extend the force), and then use sin(angle) to resolve the force into its component. Of course this is not right, so, why this is wrong. why?

Homework Equations

http://img860.imageshack.us/img860/513/xisu.png

Uploaded with ImageShack.us

The Attempt at a Solution

where did i mess up? horizontal is 36 degree, and cos 36 will give x, and sin 36 will give y. but why this is not right?

The last quote is pretty close to the answer. Now you just have to put an x-y coordinate system on the drawing (like with +x pointing right and +y pointing up), and give the x and y components of that vector in (x,y) coordinates.

 

[NascentOxygen]

When you resolve a force into its components, none of the components can have a magnitude greater than the force itself.

If you always bear this in mind, then you will correctly sketch the triangle for resolution of forces without confusion.

The components must add together vectorially to equal the force.

They must form a closed triangle of forces: horiz comp + vert comp = force