If a body covers first half of its journey with uniform speed `v_(1)` and the second half of the journey with uniform speed `v_(2)`. Then the average speed is

Options

A. `(v_(1)+v_(2))/(2)`
B. `(2v_(1)+v_(2))/(v_(1)+v_(2))`
C. `(2v_(1)v_(2))/(v_(1)+v_(2))`
D. `(L(v_(1)+v_(2)))/(v_(1)v_(2))`

Answer

C

Explanation

Total time `=t_(1)+t_(2)`
`=(l)/(2v_(1))+(l)/(2v_(2))=(l)/(2)[(1)/(v_(1))+(1)/(v_(2))]`