Another Mechanics problem. (Equilibrium)

[andorei]

HAHA. Here I am again. Now I know that most of you this is just a piece of cakeee..
Well for me, the cake is a lie. It's HAAARRDD. Most especially if you're a newbie. HAHA


"A girl weighing 620N sits in the middle of a 2.8m long hammock which sags 1.2m below the point of support. What force is exerted by each of the ropes supporting the hammock?"

I need some guidance. AGAIN. Thanks.

 

[Pi-Bond]

Drawing a diagram showing the length, sag and forces can be beneficial. Ultimately you want to express the condition for equilibrium; you need an angle for that, which can be found from the diagram.

 

[andorei]

Yup, I did that but I disregarded the sag. I only calculated the tensions on both ropes which is I think is wrong.

 

[Pi-Bond]

Can you show your diagram?

 

[PeterO]

Yup, I did that but I disregarded the sag. I only calculated the tensions on both ropes which is I think is wrong.

You must include the sag.

 

[andorei]

No diagram is given and I haven't made one yet.

But I think using the first condition of equilibrium is the one to be used.

\SigmaF_x = 0
\SigmaF_y = 0

Summation of all forces must be equal to zero, amirite?

I just don't know how to pull this off.

Our teacher never taught us about the sags or they way it will sag because of the forces acting on it.

 

[SteamKing]

I guess your teacher never showed you how to sit in a hammock, either.

 

[Pi-Bond]

Use your common sense; which direction can a rope sag in if you sit on it?

 

[andorei]

Use your common sense; which direction can a rope sag in if you sit on it?

The ropes will sag on the center. Then what now?

 

[Pi-Bond]

Right, it sags in the center, but which direction? (Up or down?)

 

[andorei]

Down. obviously.

 

[Pi-Bond]

Draw a diagram with all this information, and show us.