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Here we can consider the starting point as A and while the object moves from A to B the displacement is considered to be positive and from B to A it is negative. Answer the following questions: Subha goes to the nearby playground from her home Answer the following questions: (i) Calculate the velocity of a car travelling with a uniform velocity covering 100 m distance in 4 seconds.(ii) Usain Bolt covers 100 m distance in 9.58 seconds. Calculate his speed. Who will be the winner if Usain Bolt comepetes with a Cheetah running at a speed of 30 m/s(iii) You are walking along east covering a distance of 4 m, then 2 m towards south, then 4 m towards west and at last 2 m towards north. You cover the total distance in 21 seconds, what is your average speed and average velocity? Total distance covered = 12 m Total time taken =21 seconds |
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Answer» (i) Velocity = \(\frac{Distance}{time}\) = \(\frac{100}{4}\) = 25 m/s (ii) Speed of Usain Bolt = 10.43 m/s Speed of Cheetah = 30 m/s ∴ Cheetah will be the winner (iii) Average speed = \(\frac{Total\,distance\, covered}{total\,time}\) = \(\frac{12 m }{21}\) = 0.571 m/s Average velocity = 0 m/s \(\frac{12 m }{21}\) = 0.571 m/s Average velocity = 0 m/s Average velocity is zero because the starting point and the finishing point is same ∴ Displacement is zero so, average velocity is also ∴Average velocity = \(\frac{Total\, displacement}{time}\) |
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