question_answer

  State which of the following situations are possible and give an example for each of these. (a) An object with a constant acceleration but with zero velocity. (b) An object moving in a certain direction with an acceleration in the perpendicular direction.                                  [NCERT]

Answer:

                  Both the situations are possible. (a) When an object is projected upwards, its velocity at the topmost point is zero even though the acceleration on it is 9.8 ms~2 (= g). Also, this situation is possible when the body is at rest (constant acceleration but with zero velocity in this case). (b) When a stone tied to a string is whirled in a circular path, the acceleration but acting on it is always at right angles, i.e., perpendicular to the direction of motion of stone.