JEE Main202224 Jun 2022Evening ShiftPhysicsWork, Power and EnergyActual
A stone of mass m , tied to a string is being whirled in a vertical circle with a uniform speed. The tension in the string is
Options
- Athe same throughout the motion.
- Bminimum when the rope is in the horizontal position.
- Cminimum at the highest position of the circular path.
- Dminimum at the lowest position of the circular path.
Correct answer
C. minimum at the highest position of the circular path.
Step-by-step solution
As the speed is constant, centripetal force required towards the centre of the circle will be same. At the top, direction of gravitational force and tension acting on the object will be same. Therefore, we can write, m g + T = m v 2 r   ⇒ T = m v 2 r - m g . Clearly in this case, tension in the string will be minimum.