Case Study Questions Class 11 Physics Chapter 10 Mechanical Properties of Solid
CBSE Class 11 Case Study Questions Physics Mechanical Properties of Solid. Important Case Study Questions for Class 11 Board Exam Students. Here we have arranged some Important Case Base Questions for students who are searching for Paragraph Based Questions Mechanical Properties of Solid.
At Case Study Questions there will given a Paragraph. In where some Important Questions will made on that respective Case Based Study. There will various types of marks will given 1 marks, 2 marks, 3 marks, 4 marks.
CBSE Case Study Questions Class 11 Physics Mechanical Properties of Solid
Case Study – 1
The pressure is then defined in a limiting sense as –
Pressure is a scalar quantity. We remind the reader that it is the component of the force normal to the area under consideration. Its dimensions are [ML-1 T-2] The SI unit of pressure is N m-2. It has been named as Pascal (Pa) in honor of the French scientist Blaise Pascal (1623-1662) who carried out pioneering studies on fluid pressure.
The French scientist Blaise Pascal observed that the pressure in a fluid at rest is the same at all points if they are at the same height. Whenever external pressure is applied on any part of a fluid contained in a vessel, it is transmitted undiminished and equally in all directions. This is another form of the Pascal’s law and it has many applications in daily life. A number of devices, such as hydraulic lift and hydraulic brakes, are based on the Pascal’s law.
The pressure of the atmosphere at any point is equal to the weight of a column of air of unit cross-sectional area extending from that point to the top of the atmosphere. At sea level, it is 1.013 × 105 Pa (1atm). Italian scientist Evangelista Torricelli (1608–1647) devised for the first time a method for measuring atmospheric pressure. This device is known as ‘mercury barometer’ the space above the mercury column in the tube which is atmospheric pressure, Pa.
Where r is the density of mercury and h is the height of the mercury column in the tube.
1) Mercury barometer is used to measure
a) atmospheric pressure
b) gauge pressure
c) both a and b
d) none of these
2) Pressure is
a) scalar
b) vector
c) tensor
d) none of these
3) State Pascal’s law.
4) What is atmospheric pressure?
5) Write applications of Pascal’s law
Answer key – 1
1) a
2) a
3) the pressure in a fluid at rest is the same at all points if they are at the same height. Whenever external pressure is applied on any part of a fluid contained in a vessel, it is transmitted undiminished and equally in all directions.
4) The pressure of the atmosphere at any point is equal to the weight of a column of air of unit cross-sectional area extending from that point to the top of the atmosphere.
5) Following are applications of Pascal’s law
a) Hydraulic lift
b) Hydraulic jack
c) Hydraulic machines
d) Hydraulic brakes
Case Study – 2
Variation of pressure with depth
Thus, the pressure P, at depth below the surface of a liquid open to the atmosphere is greater than atmospheric pressure by an amount rgh. The excess of pressure, P − Pa, at depth h is called a gauge pressure at that point. The area of the cylinder is not appearing in the expression of absolute pressure. Thus, the height of the fluid column is important and not cross-sectional or base area or the shape of the container. The liquid pressure is the same at all points at the same horizontal level called as hydrostatic paradox. The flow of the fluid is said to be steady if at any given point, the velocity of each passing fluid particle remains constant in time. This does not mean that the velocity at different points in space is same. The velocity of a particular particle may change as it moves from one point to another. That is, at some other point the particle may have a different velocity, but every other particle which passes the second point behaves exactly as the previous particle that has just passed that point. Each particle follows a smooth path, and the paths of the particles do not cross each other. The path taken by a fluid particle under a steady flow is a streamline. It is defined as a curve whose tangent at any point is in the direction of the fluid velocity at that point. For steady flow equation of continuity hold good and it is a statement of conservation of mass in flow of incompressible fluids. In general
Av = constant
Av gives the volume flux or flow rate and remains constant throughout the pipe of flow. Thus, at narrower portions where the streamlines are closely spaced, velocity increases and it’s vice versa. Steady flow is achieved at low flow speeds. Beyond a limiting value, called critical speed, this flow loses steadiness and becomes turbulent. One sees this when a fast flowing stream encounters rocks, small foamy whirlpool-like regions called white water rapids are formed.
1) The flow of the fluid is said to be steady if at any given point, the velocity of each passing fluid particle
a) Remains constant in time
b) changes continuously
c) continuously increasing
d) None of these
2) According to equation of continuity area is
a) Directly proportional to velocity
b) Inversely proportional to velocity
c) Does not depends upon velocity
d) None of these
3) Give equation of continuity
4) Write a note on Variation of pressure with depth. Give its formula
5) What is hydrostatic paradox?
Answer key – 2
1) a
2) b
3) For steady flow equation of continuity hold good and it is a statement of conservation of mass in flow of incompressible fluids. In general
Av = constant
Av gives the volume flux or flow rate
4)
Thus, the pressure P, at depth below the surface of a liquid open to the atmosphere is greater than atmospheric pressure by an amount rgh. The excess of pressure, P − Pa, at depth h is called a gauge pressure at that point.
5) The liquid pressure is remains the same at all points at the same horizontal level independent on area at base called as hydrostatic paradox.
Case Study – 3
The pressure of the atmosphere at any point is equal to the weight of a column of air of unit cross-sectional area extending from that point to the top of the atmosphere. At sea level, it is 1.013 × 105 Pa (1 atm). Italian scientist Evangelista Torricelli (1608–1647) devised for the first time a method for measuring atmospheric pressure.
Where r is the density of mercury and h is the of the mercury column in the tube In the experiment it is found that the mercury column in the barometer has a height of about 76 cm at sea level equivalent to one atmosphere (1 atm). This can also be obtained using the value of r. A common way of stating pressure is in terms of cm or mm of mercury (Hg). A pressure equivalent of 1 mm is called a torr (after Torricelli). 1 torr = 133 Pa. The mm of Hg and torr are used in medicine and physiology. In meteorology, a common unit is the bar and millibar.1 bar = 105 Pa. An open tube manometer is a useful instrument for measuring pressure differences.
1) Who gave for the first time a method for measuring atmospheric pressure?
a) Newton
b) Pascal
c) Torricelli
d) None of the above
2) 1 torr is equal to
a) 1000 pa
b) 133 pa
c) 50 pa
d) None of these
3) What is 1 torr? Where it is used?
4) Which device is used for measurement of pressure difference?
5) What is atmospheric pressure?
Answer key-3
1) c
2) b
3) A pressure equivalent of 1 mm is called a torr 1torr = 133 Pa.
The mm of Hg and torr are used in medicine and physiology.
4) An open tube manometer is a useful instrument for measuring pressure differences.
5) The pressure of the atmosphere at any point is equal to the weight of a column of air of unit cross-sectional area extending from that point to the top of the atmosphere. At sea level, it is 1.013 × 105 Pa (1 atm). 76 cm at sea level equivalent to one atmosphere (1 atm).
Case Study – 4
Whenever external pressure is applied on any part of a fluid contained in a vessel, it is transmitted undiminished and equally in all directions. This is another form of the Pascal’s law and it has many applications in daily life. A number of devices, such as hydraulic lift and hydraulic brakes, are based on the Pascal’s law. In these devices, fluids are used for transmitting pressure.
Fluid flow is a complex phenomenon. Bernoulli’s principle helps in explaining blood flow in artery. The artery may get constricted due to the accumulation of plaque on its inner walls. In order to drive the blood through this constriction a greater demand is placed on the activity of the heart. The speed of the flow of the blood in this region is raised which lowers the pressure inside and the artery may collapse due to the external pressure. The heart exerts further pressure to open this artery and forces the blood through. As the blood rushes through the opening, the internal pressure once again drops due to same reasons leading to a repeat collapse. This may result in heart attack.
Dynamic lift is the force that acts on a body, such as airplane wing, a hydrofoil or a spinning ball, by virtue of its motion through a fluid. In many games such as cricket, tennis, baseball, or golf, we notice that a spinning ball deviates from its parabolic trajectory as it moves through air. This deviation can be partly explained on the basis of Bernoulli’s principle. A ball which is spinning drags air along with it. If the surface is rough more air will be dragged. shows the streamlines of air for a ball which is moving and spinning at the same time. The ball is moving forward and relative to it the air is moving backwards. Therefore, the velocity of air above the ball relative to the ball is larger and below it is smaller .The stream lines, thus, get crowded above and rarified below. This difference in the velocities of air results in the pressure difference between the lower and upper faces and there is a net upward force on the ball. This dynamic lift due to spining is called Magnus effect.
The Venturi-meter is a device to measure the flow speed of incompressible fluid. The principle behind this meter has many applications. The carburetor of automobile has a Venturi channel (nozzle) through which air flows with a high speed. The pressure is then lowered at the narrow neck and the petrol (gasoline) is sucked up in the chamber to provide the correct mixture of air to fuel necessary for combustion. Filter pumps or aspirators, Bunsen burner, atomisers and sprayers used for perfumes or to spray insecticides work on the same principle.
1) The Venturi-meter is a device used to measure the
a) Flow speed of incompressible fluid.
b) Area occupied by fluid.
c) Volume occupied by fluid
d) None of these
2) hydraulic brakes works on principle of
a) Pascal’s law
b) Newton’s law
c) Bernoulli’s principle
d) None of these
3) With the help of Bernoulli’s principle. How heart attack happens?
4) Explain Magnus effect with example of ball with spin in air.
5) What is dynamic lift?
Answer key – 4
1) a
2) a
3) With the help of Bernoulli’s principle we can explain heart attack phenomenon. The artery may get constricted due to the accumulation of plaque on its inner walls. In order to flow the blood through this constriction a large pressure is exerted on heart. The speed of the flow of the blood in this region is raised which lowers the pressure inside and the artery may collapse due to the external pressure. The heart exerts further pressure to open this artery and forces the blood through. As the blood flows fast trough the opening, the internal pressure once again drops due to same reasons leading to a repeat collapse. This result in heart attack.
4) A ball which is spinning drags air along with it. If the surface is rough more air will be dragged. When ball is moving forward and relative to it the air is moving backwards. Therefore, the velocity of air above the ball relative to the ball is larger and below it is smaller. This difference in the velocities of air results in the pressure difference between the lower and upper faces and there is a net upward force on the ball. This dynamic lift due to spining is called Magnus effect.
5) Dynamic lift is the force that acts on a body due to its motion through a fluid. In many games such as cricket, tennis, we notice that a spinning ball deviates from its parabolic trajectory this is nothing but dynamic lift.
Class 11 Physics Mechanical Properties of Fluid