InterviewSolution
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InterviewSolution
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11. A person throws a ball vertically upwards with velocity 20 m s-1 from the top of a building of height h and simultaneously throws another ball with same velocity in downward direction. If the ratio of the time taken by two balls to reach the ground is 5: 2, then the height of the building is m. (Take g = 10 m s-2) 800 9 (a) (b) 9 800 400 3 (0) (d) 3 |
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Answer» Answer: CORRECT option is A Explanation: Correct option is A solution t=5S Time to reach maximum height can be obtained from v=u+at 0=20+(−10)t t=2s s=ut+0.5at =20(2)+0.5(−10)(2) 2 =20m Thus, total distance for maximum height is 45 m s=ut+0.5at 2
45=0+0.5(10)(t ′ ) 2
t ′ =3s Total time= 3+2= 5s |
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