question_answer

                                A uniform sphere of weight W and radius 5cm is being held by a string as shown in the figure. The tension in the string will be:          JEE Main Online Paper (Held On 09 April 2013)         

A)                 \[12\frac{W}{5}\]                

B)                 \[5\frac{W}{12}\]                

C)                 \[13\frac{W}{12}\]                

D)                 \[13\frac{W}{12}\]                

Correct Answer: C

Solution :

                                                \[T\cos \theta =w\]                 \[T=\frac{w}{\cos \theta }\]                 \[\cos \theta =\frac{AB}{AC}=\frac{AB}{AD+BC}=\frac{AB}{8+5}=\frac{AB}{13}\]                 From right angle triangle \[AB=12\]                 So \[T=\frac{w\times 13}{12}\]