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A graph in Fig. 4.28 shows the change in position with time for two objects A and B moving in a straight line from 0 to 10 seconds. Choose the correct option(s). (i) The average velocity of both over the 10 s interval is equal since they have the same initial and final positions. (ii) The average speeds of both over the 10 s interval are equal since both cover equal distance in equal time. (iii) The average speed of A is lower than that of B since it covers a shorter distance. (iv) The average speed of A is greater than that of B since B’s speed is lower in some segments.
Show Answer
Correct: (i) and (ii) .
Both have the same initial and final positions, so their displacement is equal → average velocity is equal . Since both move in one direction (positions only increase), the total distance equals the displacement for each, so they also cover equal distance in equal time → average speeds are equal. Hence (iii) and (iv) are wrong.
