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A motorist drives north for 35.0 min at 85 km/h and then stops for 15 min . He continues travelling north and covers 130 km in 2 hours . What is his total displacement and average velocity |
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Answer» Answer: Total DISPLACEMENT : 179.3 Km Average Velocity : 69.4 m/s Explanation: A.T.Q. Let B be the place at which he stopped Velocity from A to B, v1 : 85 km/h Time TAKEN, From A to B, T1 : 35 min = 0.58 hr From B to C, t2 : 2 hr Displacement, From A to B, s1 : v1 x t1 = (85 x 0.58) Km = 49.3 Km From B to C, s2 : 130 Km Total Time taken : t1 + t2 = 0.58 + 2 = 2.58 hr Now, Total Displacement : s1 + s2 = 49.3 + 130 Km = 179.3 Km Also, Average Velocity : Total Displacement/Total Time Taken = (s1 + s2)/(t1 + t2) = 179.3/2.58 = 69.4 m/s |
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