question_answer

A ball of mass 0.3 kg is tied to one end of a string 0.8 m long and rotated in a vertical circle. If the tension in the string be zero at the highest point of the circle, the tension at the lowest point in this situation will be equal to

A)  zero                                     

B)  2.94 N

C)  17.6 N                                 

D)  19.60 N

Correct Answer: C

Solution :

                 Given, m = 0.3 kg and 1 = 0.8m                 \[\because \]     \[{{T}_{A}}-{{T}_{C}}=6\]mg                                                                  The tension at the lowest point                 \[{{T}_{A}}=6mg\]                           \[[\because {{T}_{C}}=0]\]                 \[=6\times 0.3\times 9.8=17.6\,N\]