Q4. A ball of mass m attached to one end of a thin, light, inextensible string moves with speed vo in a circle of radius ro in free space. Calculate the work required to reduce the radius from rotor by pulling the other end of the string through a smooth tube that is perpendicular to the plane of the circle. Express the result in terms of m, vo, ro and r. (HINTS: 1) Tension in the string is a central force and therefore the angular momentum is conserved 2) If radius changes then the speed changes, hence the KE. (Use work-energy theorem) See the representative figure given below: So m.

Q4. A ball of mass m attached to one end of a thin, light, inextensible string moves with speed vo in a circle of radius ro in free space. Calculate the work required to reduce the radius from rotor by pulling the other end of the string through a smooth tube that is perpendicular to the plane of the circle. Express the result in terms of m, vo, ro and r. (HINTS: 1) Tension in the string is a central force and therefore the angular momentum is conserved 2) If radius changes then the speed changes, hence the KE. (Use work-energy theorem) See the representative figure given below: So m.