Question
Physics Question on Motion in a straight line
The position-time (x-t) graphs for two children A and B returning from their school O to their homes P and Q respectively are shown in Fig. 2.9. Choose the correct entries in the brackets below ;
- (A/B) lives closer to the school than (B/A)
- (A/B) starts from the school earlier than (B/A)
- (A/B) walks faster than (B/A)
- A and B reach home at the (same/different) time
- (A/B) overtakes (B/A) on the road (once/twice).
a. A lives closer to school than B.
b. A starts from school earlier than B.
c. B walks faster than A.
d. A and B reach home at the same time.
e. B overtakes A once on the road.
Explanation:
In the given x–t graph, it can be observed that distance OP < OQ. Hence, the distance of school from the A’s home is less than that from B’s home.
In the given graph, it can be observed that for x = 0, t = 0 for A, whereas for x = 0, t has some finite value for B. Thus, A starts his journey from school earlier than B.
In the given x–t graph, it can be observed that the slope of B is greater than that of A. Since the slope of the x–t graph gives the speed, a greater slope means that the speed of B is greater than the speed A.
It is clear from the given graph that both A and B reach their respective homes at the same time.
B moves later than A and his/her speed is greater than that of A. From the graph, it is clear that B overtakes A only once on the road.