A car moves with speed of 30km/hr for 3hrs and 40km/hr for 2hrs. What is the magnitude of average velocity?
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A car moves with speed of 30km/hr for 3hrs and 40km/hr for 2hrs. What is the magnitude of average velocity?
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Answer:
Distance covered in half an hour at 30km/hr = s×t = 30×1/2=15km.
Distance coveted in 1hr at 25km/hr= s×t= 25×1 =25km.
Distance covered in 2 hrs at 40km/hr=s×t= 40×2=80km
Therefore, total distance covered= 15+25+80=120km
Total time taken= 3hrs and 30 mins=7/2 hrs.
Therefore, average speed=total distance covered/total time taken = 120×2/7 = 34.28km/hr
Explanation:
Distance covered in half an hour at 30km/hr = s×t = 30×1/2=15km.
Distance coveted in 1hr at 25km/hr= s×t= 25×1 =25km.
Distance covered in 2 hrs at 40km/hr=s×t= 40×2=80km
Therefore, total distance covered= 15+25+80=120km
Total time taken= 3hrs and 30 mins=7/2 hrs.
Therefore, average speed=total distance covered/total time taken = 120×2/7 = 34.28km/hr