Question -
| Lowest Point | Highest Point |
| (a) | mg – T1 | mg + T2 |
| (b) | mg + T1 | mg – T2 |
| (c) | mg + T1 – /R | mg – T2 + /R |
| (d) | mg – T1 – /R | mg + T2 + /R |
T1 and v1 denotethe tension and speed at the lowest point. T2 and v2 denotecorresponding values at the highest point.
Answer -
(a)The free body diagram of the stone at thelowest point is shown in the following figure.
Accordingto Newton’s second law of motion, the net force acting on the stone at thispoint is equal to the centripetal force, i.e.,
Where, v1 =Velocity at the lowest point
Thefree body diagram of the stone at the highest point is shown in the followingfigure.
UsingNewton’s second law of motion, we have:
… (ii)
Where, v2 =Velocity at the highest point
Itis clear from equations (i) and (ii) that the net force acting atthe lowest and the highest points are respectively (T – mg)and (T + mg).