By definition, the average speed is given as total distance divided by total time:
vav=t1+t2d1+d2 where d1,d2 are the parts of total distance covered during times t1=10min=600s,t2=10min=600s with speeds v1=15m/s,v2=25m/s respectively.
For the first half of the journey, obtain:
d1=v1t1 For the second half:
d2=v2t2 Finally, obtain:
vav=t1+t2v1t1+v2t2=600+60015⋅600+25⋅600=20m/s Answer. equal to 20 m/s.
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