Answer:
(A) 0.625 m /sec
(B) 0 m /sec
(C) 0.692 m /sec
(d) 0.692 m /sec
Explanation:
We have given that a runner covers one lap of track which is 40 m in length in 64 sec
(a) Average speed will be equal to ratio of distance traveled and time taken
So average speed
(B) Average velocity is the ratio of displacement and time taken
As he completed one lap means comes to his initial position
So displacement will be zero
So average velocity
(C) Here time is 28.9 sec for half lap
So average speed
(D) For half lap displacement will be equal to distance traveled
So average velocity will be equal to v=\frac{s}{t}=\frac{20}{28.9}=0.6920m/sec
The answer is 20km because you go to yours friend's house and back then an extra 10km. 5+5+10=20km
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