(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A small sphere of weight W is held as shown by two wires AB and CD. If wire AB is cut, determine the tension in the other wire (a) before AB is cut, (b) immediately after AB has been cut. (Ans: (a) TCD = 0.742 W; (b) TCD = 0.940 W).

http://img4.imageshack.us/img4/3763/picture11td.png [Broken]

2. Relevant equations

[tex]\Sigma[/tex]F_{y}=ma_{y}

T_{y}=Tsin[tex]\theta[/tex]

3. The attempt at a solution

T_{CDy}+T_{ABy}-W=ma_{y}; a_{y}=0 (not moving)

T_{CD}Sin(70^{[tex]\circ[/tex]})+T_{AB}Sin(50^{[tex]\circ[/tex]})-W=0 ; solve fot T_{AB}and plug in

T_{AB}Sin(50^{[tex]\circ[/tex]})=W-T_{CD}Sin(70^{[tex]\circ[/tex]}) ; divide Sin(50^{[tex]\circ[/tex]}) from both sides

T_{AB}=[W/Sin(50^{[tex]\circ[/tex]})]-[T_{CD}Sin(70^{[tex]\circ[/tex]})/Sin(50^{[tex]\circ[/tex]})]

T_{CD}Sin(70^{[tex]\circ[/tex]})+[W/Sin(50^{[tex]\circ[/tex]})]-[T_{CD}Sin(70^{[tex]\circ[/tex]})/Sin(50^{[tex]\circ[/tex]})]-W=0 ; Plugging in T_{AB}from above

T_{CD}(Sin(70^{[tex]\circ[/tex]})-(Sin(70^{[tex]\circ[/tex]})/(Sin(50^{[tex]\circ[/tex]})=W(1-1/(Sin(50^{[tex]\circ[/tex]})

Solving for T_{CD}I get 1.066W when its supposed to be 0.742 W

What am i doing wrong?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Tension; 2 cables holding weight

**Physics Forums | Science Articles, Homework Help, Discussion**