The figure shows a mass m=2kg moving in a circle at constant speed which is attached to a rotating rod by two strings of length L-0.3m. The distance between where the strings attach to the rod is given by d=0.25m. What is the tension in the upper string if the mass has the speed v required for the bottom string to have zero tension? (A) 29N (B) 18N (C) 34N (D) 21N (E) 47N Rotating rod

The figure shows a mass m=2kg moving in a circle at constant speed which is attached to a rotating rod by two strings of length L-0.3m. The distance between where the strings attach to the rod is given by d=0.25m. What is the tension in the upper string if the mass has the speed v required for the bottom string to have zero tension? (A) 29N (B) 18N (C) 34N (D) 21N (E) 47N Rotating rod