A particle is in linear S.H.M. between two points A and B, 10 cm apart. Take the direction from A to B as the positive direction and give the signs of velocity, acceleration and force on the particle when it is.
(a) at the end A (b) at the end B,
(c) at the mid point of AB going towards A,
(d) at 2 cm away from B going towards A,
(e) at 3 cm away from A goiing towards B, and
(f) at 4 cm away from A going towards A.

Explanation

In the fig. (given below), the points A and B, 10 cm apart, are the extreme positions of the particle in SHM, and the point O is the mean position. The direction from A to B is positive, as indicated.

(a) At the end A, i.e., extreme position, velocity is zero, acceleration and force are directed towards O and are positive.
(b) At the end B i.e., second extremen position, velocity is zero whereas the acceleration and force are directed towards the point O and are negative.
(c) At the mid point O, while going towards A, velocity is negative and maximum. The accelerationa and force both are zero.
(d) At 2 cm away from B, that is, at C and going towards A: v is negative, acceleration and F, being directed towards O, are also negative.
(e) At 3 cm away from A, that is, at D and going towards B: v is positivel acceleration and F, being directed towards O, are also positive.
(f) At a distance of 4 cm away from A and going towards A, velocity is directed along BA, therefore, it is positive. Since acceleration and force are directed towards OB, both of them are positive.