question_answer

A string of length L and mass m are lying on a horizontal table. A force F is applied at one of its ends. Tension in the string at a distance X from the ends at which force is applied is:

A)  zero                

B)  F

C)  \[F(L-X)L\]                 

D)  \[F(L-X)/M\]

Correct Answer: C

Solution :

As, acceleration   \[a=\frac{f}{m}\] From FED we get             \[F-T=\frac{M}{L}\,(x)\,a\] \[\Rightarrow \]               \[T=F\left( 1-\frac{X}{L} \right)\] \[\Rightarrow \]               \[T=\frac{F(L-X)}{L}\]