The position-time graph for four objects A, B, C and D moving along a straight line. Class 9

The position-time graph for four objects A, B, C and D moving along a straight line. Class 9

Question 1.

The position-time graph for four objects A, B, C and D moving along a straight line are given in Fig. A net force acts on: Class 9

(i) Object A

(ii) Object B

(iii) Object C

(iv) Object D

Answer:

A net force acts only on objects whose acceleration is non-zero.

1. Object A: Position-time graph is a straight line with constant slope → constant velocity → acceleration = 0 → no net force.
2. Object B: Position-time graph is a horizontal line → object is at rest → acceleration = 0 → no net force.
3. Object C: Position-time graph is a curve with increasing slope → velocity is increasing → acceleration ≠ 0 → net force acts.
4. Object D: Position-time graph is a curve with decreasing slope → velocity is decreasing → acceleration ≠ 0 → net force acts.