In the previous question, at the mouth of the tap the area of cross-section is `2.5 cm^2` and the speed of water in `3 m//s`. The area of cross-section of the water column `80 cm` below the tap is.

Options

A. `2 cm^2`
B. `1.5 cm^2`
C. `1 cm^2`
D. `0.5 cm^2`

Answer

B

Explanation

`A_1 = 2.5 cm^2, v_1 = 3 m//s, h = 0.8 m, A_2 = ?`
`v_(2)^(2) = v_(1)^(2) + 2gh = (3)^2 + 2 xx 10 xx 0.8 = 25`
`v_2 = 5 m//s`
`A_1 v_1 = A_2 v_2`
`2.5 xx 3 = A_2 xx 5`
`A_2 = 1.5 cm^2`.