question_answer

One end of a string of length 1.0 m is tied to a body of mass 0.5 kg. It is whirled in a vertical circle with angular frequency 4 rad/s. The tension in the string, when the body is at the lower most point of its motion, will be equal to (Take \[g=10\,\,m/{{s}^{2}}\])

A)  3 N                                       

B)  5 N

C)  8 N                                       

D)  13 N

Correct Answer: D

Solution :

                 Tension \[T=m{{\omega }^{2}}r+mg\] \[=0.5\times {{(4)}^{2}}\times 1+0.5\times 10=13\,N\]