2_Hydraulics Practice Quiz with Answer and Solution

Refresher - HYDRAULICS Quiz 2
PROBLEM 1:

For lack of mercury, an improved barometer usws a liquid which was
observed to weigh 0.735 times that of mercury. At the base of the
mountain the barometer reads 850 mm. Concurrently another barometer
of the same kind at the top of the mountain reads 600 mm. Assuming the
unit weight of air to be constant at 12 N/m3, evaluate the height of the
mountain in km.


2


h

1




Solution:
P1 = P2 + y air h
12 h
9.81(13.6)(0.735)(0.850) = 9.81(13.6)(0.735)(0.600) +
1000
h = 2042.9 m.
h = 2.04 km

, Refresher - HYDRAULICS Quiz 2
PROBLEM 2:

A ship, with vertical sides near the waterline, weighs 40 MN including its cargo
and has a draft of 6.7 meters in seawater (s.g. = 1.026). Unloading 2 MN of its
cargo, the draft decreases to 6.4 m. With its cargo reduced, the ship enters a
harbor of fresh water. Evaluate the draft of the ship in fresh water, in meters.

Solution: 40000 kN

➊ 40000 + W = BF1
40000 + W = 9.81(6.7)(A) (1.026) w.s.

40000 + W = 67.44A W
W = 67.44A – 40000 6.7 m


sea water sp. gr. = 1.026
BF1

➋ 38000 + W = BF2
38000 + W = 9.81(6.4)(A)(1.026) 38000 kN
38000 + 67.44A – 40000 = 64.42A
3.02A = 2000 w.s.
A = 662.25 m2
W = 67.44(662.25) - 40000 W
6.4 m
W = 4662.14
sea water sp. gr. = 1.026
BF2


➌ 38000 + W = BF3
38000 kN
38000 + 4662.14 = 9.81(d)(622.25)
d = 6.56 m. w.s.


W
d


Fresh water sp. gr. = 1.0
H2O
BF3