Fluid Mechanics Questions and Answers – Fluid Properties – 1

This set of Fluid Mechanics Multiple Choice Questions & Answers (MCQs) focuses on “Fluid Properties – 1”.

1. Which one of the following is the unit of mass density?
a) kg = m3
b) kg = m2
c) kg = m
d) kg = ms

Answer: a
Explanation: Mass Density(p) is defined as the mass(m) per unit volume(V ), i.e., p = m ⁄v
Thus, the unit of p is kg = m3.

2. The specific gravity of a liquid has
a) the same unit as that of mass density
b) the same unit as that of weight density
c) the same unit as that of specific volume
d) no unit

Answer: d
Explanation: The specific gravity of a liquid is the ratio of two similar quantities (densities) which makes it unitless.

3. The specific volume of a liquid is the reciprocal of
a) weight density
b) mass density
c) specific weight
d) specific volume

Answer: b
Explanation: Specific volume(v) is defined as the volume(V ) per unit mass(m).
v = v⁄m = 1 / m⁄v = 1⁄p
where p is the mass density.

4. Which one of the following is the unit of specific weight?
a) N = m3
b) N = m2
c) N = m
d) N = ms

Answer: a
Explanation: Specific weight(γ) is defined as the weight(w) per unit volume(V ), i.e.,
γ = w / v
Thus, unit of is N = m3.

5. Which one of the following is the dimension of mass density?
a) [M1 L-3 T0].
b) [M1 L3 T0].
c) [M0 L-3 T0].
d) [M0 L3 T0]

Answer: a
Explanation: Mass Density(p) is defined as the mass(m) per unit volume(V ), i.e.,
[p] = [m]/[v] = [m] /[L3] = [ML-3].

6. Which one of the following is the dimension of specific gravity of a liquid?
a) [M1 L-3 T0].
b) [M1 L0 T0].
c) [M0 L-3 T0].
d) [M0 L0 T0].

Answer: d
Explanation: The specific gravity of a liquid is the ratio of two similar quantities (densities) which makes it dimensionless.

7. Which one of the following is the dimension of specific volume of a liquid?
a) [M1 L-3 T0].
b) [M-1 L3 T0].
c) [M-1 L-3 T0].
d) [M0 L3 T0].

Answer: b
Explanation: Specific volume(v) is defined as the volume(V ) per unit mass(m). Thus,
[v] = [V]/[m] = [L3]/[M] = [M-1L3].

8. Which one of the following is the dimension of specific weight of a liquid?
a) [ML-3 T -2].
b) [ML3 T-2].
c) [ML-2 T-2].
d) [ML2 T-2].

Answer: c
Explanation: Specific weight(γ) is defined as the weight(w) per unit volume(V ), i.e.,

9. Two fluids 1 and 2 have mass densities of p1 and p2 respectively. If p1 > p2, which one of the following expressions will represent the relation between their specific volumes v1 and v2?
a) v1 > v2
b) v1 < v2
c) v1 = v2
d) Cannot be determined due to insufficient information.

Answer: b
Explanation: Specific volume(v) is defined as the volume(V ) per unit mass(m).
v = v⁄m = 1 / m⁄v = 1⁄p
where p is the mass density. Thus, if p1 > p2, the relation between the specific volumes v1 and v2
will be represented by v1 < v2.

10. A beaker is filled with a liquid up to the mark of one litre and weighed. The weight of the liquid is found to be 6.5 N. The specific weight of the liquid will be
a) 6:5 kN = m3
b) 6:6 kN = m3
c) 6:7 kN = m3
d) 6:8 kN = m3

Answer: a
Explanation: Specific weight(γ) is defined as the weight(w) per unit volume(V ), i.e.,
γ = w⁄V
Thus, γ = 6:5 ⁄10-3 N ⁄ m3 = 6:5 kN/m3.

11. A beaker is filled with a liquid up to the mark of one litre and weighed. The weight of the liquid is found to be 6.5 N. The specific gravity of the liquid will be
a) 0.65
b) 0.66
c) 0.67
d) 0.68

Answer: b
Explanation: Specific gravity(S) of a liquid is defined as the ratio of the density of the liquid(pl) to that of water(pw).

Thus, S = 0:66.

12. A beaker is filled with a liquid up to the mark of one litre and weighed. The weight of the liquid is found to be 6.5 N. The specific volume of the liquid will be
a) 1 l =kg
b) 1:5 l =kg
c) 2 l =kg
d) 2:5 l =kg

Answer: b
Explanation: Specific volume(v) is defined as the volume(V ) per unit mass(m). Thus,

WHY MECHANICAL ENGINEERING IS BETTER ????

Over the past few decades, mechanical engineering degree has raised its value and demand among aspirants and no decline has yet been seen in reputation and scope of mechanical engineering degree. That is why it is often said to be an ever green field.

Mechanical Engineering is a diverse field of engineering. This diversity allows mechanical engineers to pursue a career in any field of life. So it gives you a wide variety of choice after graduation. There are many students who wish to change their field of work after they graduate. So if you are a mechanical engineer, you will find it easy to plunge yourself into a completely new field. Either you want to be a project manager or a technical consultant, being a mechanical engineer you can survive in any field.
    I know many mechanical engineers who are doing awesome jobs as environmentalists because they did masters in environmental engineering after bachelors in mechanical. This is why I said mechanical engineering is diverse in its scope, Even if you don’t like to be a mechanical engineer at work, you can change your path easily. You can pursue higher education in civil engineering, environmental engineering, computer science, software engineering, quality control, project management or even supply chain management. Swapping field of work is not difficult for mechanical engineers.

A Different Kind of Heart Attack: New Research Finds a Broken Heart Permanently Weakens the Organ in a Similar Way

Researchers discover that severe emotional distress can damage the heart physically like a heart attack.

At least 3,000 adults in the U.K. suffer from Takotsubo cardiomyopathy, colloquially termed as the “broken heart syndrome,” each year. It is caused by bereavement and severe emotional distress, which stuns and weakens the heart. This causes the left ventricle – one of the main chambers of the heart – to change shape.

The deformed heart looks similar to an octopus pot, or “takotsubo” in Japanese, which gave the condition its name. Doctors have long presumed that the damage was temporary and would eventually heal over time. ( Broken hearts may actually be able to cause death.)

Interestingly, a major project by Swiss researchers last year found that the condition can also be triggered by extreme happiness as well as sorrow.

Researchers at the University of Aberdeen have discovered that the condition may cause permanent damage to the heart, similar to a heart attack. Following 37 patients with Takotsubo for two years, they found that the heart damage remained long after the event that first triggered the condition. This was seen through regular ultrasound and MRI scans.

Many of the patients reported becoming tired very easily and were thus unable to do much exercise. The researchers suggest that patients should be offered the same drugs as those whose hearts have been damaged by a heart attack.

Lead researcher Dr. Dana Dawson said that Takotsubo is more common than they initially thought, and that it may actually cause permanent damage to the hearts of the patients. Moreover, the condition is affecting the patients’ everyday lives with frequent exhaustion and lack of physical activity.

“Our research shows that Takotsubo needs to be treated with same urgency as any other heart problem, and that patients may need ongoing treatment for these long-term effects,” said Dr. Dawson.

Furthermore, the study suggests that women are more prone to developing this condition than men.

 Treat your heart to some of these healing herbs:

• 1.Hawthorn (Crataegus spp.) – This helps strengthen the cardiovascular system, lower your cholesterol levels, and maintain a healthy blood pressure. One way to prepare it is to crush its (dried) berries and add a teaspoon of it with some sweetener in a cup of hot water, to sip as tea.
• 2.Lemon balm (Melissa officinalis) – This herb is most helpful in relieving insomnia and restlessness, that may be caused by intense emotional stress like heartbreak. Add two teaspoons of dried lemon balm, a little bit of sweetener, and lemon juice to a cup of hot water for a flavorful tea.
• 3.Rose petals (Rosa rugosa) – The rose has long been a symbol of love, whether romantic (red rose) or platonic (yellow rose). Roses can calm the nerves and soothe physical fatigue. A tablespoon of rose petals and some light-flavored honey mixed in hot water is the perfect mood-lifter.