A train has a speed of 60, km/h . for first one hour and 40, km/h for next half hour. Its average sp

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2.Motion in Straight Line

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A train has a speed of $60\, km/h$. for the first one hour and $40\, km/h $ for the next half hour. Its average speed in $km/h$ is

A

$50$

B

$53.33$

C

$48$

D

$70$

Solution

(b) Distance travelled by train in first $1$ hour is $60 \,km$ and distance in next $1/2 \,hour $ is $20 \,km$.

So Average speed $ = \frac{{{\rm{Total\, distance }}}}{{{\rm{Total \,time }}}} = \frac{{60 + 20}}{{3/2}}$

$ = 53.33\;km/hour$

Standard 11

Physics

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