Topic: Mechanical Properties of Fluids (Test 1)



Topic: Mechanical Properties of Fluids
Q.1
The basic property of a fluid that makes it different from solids
A. it can be compressed
B. it does not expands very little on heating
C. is that it can flow
D. it has a large density
Answer : Option C
Explaination / Solution:

fluids can flow due to unbalanced forces between the atoms of fluids.

Workspace
Report
Q.2
Density is defined as
A. volume of 10 kg of the material
B. volume of 1 kg of the material
C. mass per unit volume
D. volume per unit mass
Answer : Option C
Explaination / Solution:

Density is defined as the compactness of substance.

Mathematically,

Density(D)= 


Workspace
Report
Q.3
The specific gravity of a material is
A. the ratio of its mass to the density of water
B. the ratio of its mass to the mass of water
C. the ratio of its density to the density of water
D. the ratio of its volume to the density of water
Answer : Option C
Explaination / Solution:

The specific gravity of an object is the ratio between the density of an object to a reference liquid. Usually, this reference liquid is water, which has a density of 1 g/mL or 1 g/cm3.

Water has a specific gravity equal to 1. Materials with a specific gravity less than 1 are less dense than water, and will float on the pure liquid; substances with a specific gravity more than 1 are more dense than water, and will sink.


Workspace
Report
Q.4
Pressure p at any point in a fluid at rest is
A. the normal force at that point per unit mass
B. the normal force at that point per unit volume
C. the force parallel to area at that point per unit area
D. the normal force at that point per unit area
Answer : Option D
Explaination / Solution:

It is important to note that it is valid only for a fluid at rest. In the case of a moving fluid, pressures in different directions could be different depending upon fluid accelerations in different directions.

Workspace
Report
Q.5
According to Pascal’s Law the
A. pressure in a fluid at rest is the same at all points if they are at different heights
B. pressure in a fluid decreases with temperature
C. pressure in a fluid at rest is the same at all points if they are at the same height
D. pressure in a fluid increases with temperature
Answer : Option C
Explaination / Solution:

According to Pascal's Law,

P-P= hdg

from above

Change in pressure is directly proportional to depth from the free surface.

At the same horizonatal line all point are at the same depth and have same value of acceleration due to gravity and denity of water as well.


Workspace
Report
Q.6

The pressure at a depth of h in a fluid of density  at a place where the acceleration due to gravity is g and the pressure at h=0 is  is given by

A. p =  gh
B. p = ρgh
C. p =  +  gh
D. p =  +  gh
Answer : Option D
Explaination / Solution:

According to Pascal's Law,

Change in Pressure (P-P0) = hg

if h=0 then P-P0 = 0

and P=P0


Workspace
Report
Q.7
The units of pressure in SI system is
A. Newton
B. Joule
C. Watt
D. Pascal
Answer : Option D
Explaination / Solution:

The SI unit for pressure is the pascal (Pa), equal to one newton per square metre (N/m2, or kg. m. s−2). This name for the unit was added in 1971; before that, pressure in SI was expressed simply in newtons per square metre

Workspace
Report
Q.8
Gauge pressure at a point is
A. pressure at that point + atmospheric pressure
B. (pressure at that point – atmospheric pressure)/2
C. pressure at that point – atmospheric pressure
D. (pressure at that point + atmospheric pressure)/2
Answer : Option C
Explaination / Solution:

Gauge pressure is zero-referenced against ambient air pressure, so it is equal to absolute pressure minus atmospheric pressure. Negative signs are usually omitted

The difference between absolute pressure and atmospheric pressure is what we call gauge pressure (). It can be calculated if we know the absolute and atmospheric pressures using this formula: 


Workspace
Report
Q.9
According to Pascal’s law for transmission of fluid pressure external pressure applied on any part of a fluid contained in a vessel is ___________________ in all directions
A. transmitted undiminished and equally
B. transmitted and decreased
C. not transmitted
D. transmitted and increased
Answer : Option A
Explaination / Solution:

Pascal's principle is defined as a change in pressure at any point in an enclosed fluid at rest is transmitted undiminished to all points in the fluid.

This principle is stated mathematically as:

 is the hydrostatic pressure (given in pascals in the SI system), or the difference in pressure at two points within a fluid column, due to the weight of the fluid.


Workspace
Report
Q.10
In a hydraulic lift the force applied on the smaller cylinder of area A1 is F1. If the area of the larger cylinder is Athe maximum weight that can be lifted is
A. F1A2
B. A1A2F1
C. F1
D. A2A1F1
Answer : Option D
Explaination / Solution:

According to Pascal's Law,

Pressure applied to any point inside the liquid is trnasmiteed equally in all direction so,

Pressure applied on the smaller cylinder is equal to the pressure on the other cylinder,which is given by


So,

Maximum force on the other side is ,

F2 = 


Workspace
Report