A scooterist travel a certain distance with speed of 50km|/h and return back at the starting points with a speed of 40km/h. Calculate average speed and average velocity of the whole journey.
Answers
Answer:
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Question ⁉️
A scooterist travel a certain distance with speed of 50 km/ h and return back at the starting points with a speed of 40 km/ h . Calculate average speed and average velocity of the whole journey.
Solution
Let the total distance covered by the scooterist be " 2D "
the scooterist covers half of the total distance that is distance " D " with speed 50 km/h
time taken to cover the initial half = D / 50 hr
then , he covers the next half distance " D " and returns back to the point( from where he started ) with speed 40 km/h
time taken to cover the next half = D / 40 hr
total distance covered = 2 D
total time taken = ( D/50 ) + ( D/40 )
= 9D / 200 hr
Average speed = Total distance covered / total time taken
= 2D / ( 9D/200 ) km/h
= 400/9 km/ h
Average velocity = total displacement / total time
since , he returned back to the point from where he started , the net displacement is ZERO
therefore,
Average velocity = 0