A person travels along a straight road for the first half length with a velocity `v_(1) ` and the second half length with velocity ` v_(2)`. What is the mean velocity of the person ?

Explanation

Time take by person to travel first half length,
` t_(1) =((d//2))/v_(1) =d/(2 v_(1)`
Time taken by person to travel second half length , `t_(2) =((d //2))/v_(2) =d/(2 v_(1))`
:. Total time ` =t_(1) + t_(2) d/2 [1/v_(1) + 1/v_(2)]`
`=(d (v_(1) + v_(2))/(2 v_91) v_(2))`
:. Mean velocity or average velocity
` =d/(t_(1) + t_(2)) =(2 u _(1) v_(2))/((v_(1) + v_(2))`.