An object moves the first half of the total distance with a speed of 2 m `s^(-1)` . If the average of the body is ` 3m s ^(-1)` , the speed of the body when it travelles the remaining distance is _______ ` m s^(-1)`

Options

A. 3
B. 6
C. 4
D. 2

Answer

B

Explanation

Let the total distance be 2d.
Then `d/t_(1)=2`
`d/t_(2)=x,`
`(2d)/(t_(1)+t_(2))=3rArrd=(3(t_(1)+t_(2)))/2`
From (1) and (2),
`2t_(1)=3((t_(1)+t_(2)))/2rArr4t_(1)=3t_(1)+3t_(2)`
`t_(1)=3t_(2)" "therefored/t_(1//3)=xrArr(3d)/t_(1)=x`
From (1),
3(2) = x
`x=6ms^(-1)`.