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The velocity-time graph (v-t) of a car moving along alevel road is shown below. The average speed of thecar in the time interval 0 to 8 s is about??? |
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Answer» Answer: 4.48 m/s Explanation: Velocity at t = 5 sec is -5 m/s Acceleration = (-5 -10)/(5 - 0) = - 3 m/s² Distance COVERED till SPEED becomes 0 using V² - U² = 2AS => S = (0² - 10²)/(2(-3)) => S = 50/3 m Distance covered from 0 velocity to - 5 = 5²/2(-3) = 25/6 m (in opposite direction) From 5 to 8 Sec Distance covered = -5 * 3 = 15 m ( in opposite direction) Total Distance Covered = 50/3 + 25/6 + 15 = 215/6 m Time = 8 sec Average Speed = (215/6)/8 = 4.48 m/s Average Velocity = (50/3 - 25/6 - 15)/8 = - 15/48 = -0.3125 m/s |
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