A container of water with an overflow tube sits on a scale that reads 40 N. The

Question

A container of water with an overflow tube sits on a scale that reads 40 N. The water level is just below the exit tube in the side of the container. A) an 8.0 N cube of water is placed in the container. The water displaced by the floating cube runs out the exit tube into another container that is not on the scale. Will the scale reading then be 1) exactly 48 N, 2) between 40 N and 48 N, 3) exactly 40 N, or 4) less than 40 N? b) suppose you pushed down the cube with your finger such that the top surface of the cube was even with the water level. How much force would have to be applied if the wooden cube measures 10 cm on a side? c) in part a, would the scale still read 40 N if the object had a density greater than that of water? answers are a) 3 b) 1.8 N c) no the scale reads more Please explain

Explanation / Answer

a) When the wooden cube is pushed down, it displaces as much water as is needed to equal its own weight, thus, it displaces 8N water. Hence, the scale reading remains the same

b) when wood (say density=d) floats,
the volume submerged=base area x submerged height (say h)
=100(cm2) x h(cm)
Also, voume of water displaced = volume of wood submerged
=100h cm3

weight of water displaced = weight of wooden cube
=> 100h x density_of_water x g = 8
From here, h can be calculated
When you are pressing the wooden piece, you are submerging (10-h)cm extra into the water, thus,
force=(10-h) x g x density_of_water x base_area(100 cm2)

c)When a denser substance is put in water, it cannot float and sinks, hence it always displaces water equal to its own volume, thus V (say) volume of water is being replaced by V volume of a denser substance. Hence the increase in weight

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.