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A car accelerates with a constant acceleration of 1.2 m/s^2 along a long straight road. How long does it take the car to accelerate from 100 kph to 110 kph, and how far does it travel while doing so? [Hint: watch your units and your significant figures. Because there is no other information, take the speeds as three significant figures.] It takes ______ seconds to accelerate to 110 kph. While accelerating, the car travels _____ m. Separate your answers with a comma. Example: a, b |
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Answer» Explanation: 100 kph=100×1000/3600=27.78 m/s 110 kph=110×1000/3600= 30.56 m/s so, CHANGE in velo. =(30.56 -27.78) m/s =2.78 m/s (approx) so time TAKEN ,t= 2.78/1.2 sec =2.32 sec (approx) now during this time car travels =(27.78 ×2.32+1/2×1.2×2.32×2.32) =67.68 m.(approx) so ans == 2.32 sec, 67.68mt. |
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