A stone of mass m tied to one end of a string is revolved in a vertical circle of radius R the net forces at the lowest `(F_(L)` and highest `(F_(H))` points of the circle directed vertically downwards are :
(a) `F_(L) = mg - T_(1) F_(H) = mg + T_(2)`
(b) `F_(L) = mg + T_(1) , F_(H) = mg - T_(2)`
(c) `F_(L) = mg + T_(1) - (m upsilon_1^(2))/(R) , F_(H) = mg - T_(2) + (m upsilon_(1)^(2))/(R )`
(d) `F_(L) = mg - T_(1) - (m upsilon_(1)^(2))/(R) , F_(H) = mg + T_(2) + (m upsilon_(2)^(1))/(R)`
Choose corret alternative `T_(1), upsilon_(1)` denote the tension and speed at the lowest point `T_(2), upsilon_(2)` denote corresponding valuse at the highest point .

Explanation

The net force at the lowest point L is `F_(L) = (mg - T_(1)` and the net force at the highest point H is `F_(H = mg + T_(2)` Thereforce alternative (a) is correct For details.