Question

Una mancha de petroleo que tiene una densidad de 930 kg /m3 flota sobre el agua. Un bloque rectangular de madera de 4.00 cm de altura y con una densidad de 960 kg / m3 flota parcialmente en el petroleo y parcialmente en el agua. El petroleo cubre por completo el bloque. ¿Que tan abajo de la superficie de contacto entre los dos liquidos esta el fondo del bloque?

An oil slick that has a density of 930 kg / m3 floats on water. A rectangular block of wood 4.00 cm high and with a density of 960 kg / m3 floats partially in oil and partially in water. The oil completely covers the block. How far below the contact surface between the two liquids is the bottom of the block?

Answer 1

Solution:

We are given following data for block of wood in oil and water alloy:

w = 1000 kg/m^3

oil = 930 kg/m^3

wood = 960 kg/m^3

h = 4 cm

Oil is above the water because density of oil is lower than density of water. Density of wood is higher than oil density but lower than water density. It means that it is positioned somewhere between the oil and water.

Equillibrium equations:

[wood * g * h] - [ oil * g * (h-x)] - [ water * g* x ] = 0

or, x = (wood - oil)*h /(water - oil) = (960 - 930)*4 / (1000-930) = 1.7 cm [Answer]