explain with suitable example importance of Anatomical evidences in evolution
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These basic mechanical engineering questions with answers will help you to get a good understanding of the mechanical engineering concepts. Let’s begin.
What does CNC stand for? CNC Meaning / CNC definition.
Answer: CNC stands for Computer Numerical Controls.
Numeric Controls creates the automation of the machine tools. If computer program is used to make the automation then the system is called CNC system. In modern times Computer Aided designs (CADs) are used in the CNC machines for precise operation.
How the value of gear train is measured?
Answer: The mechanical system which engages two or more gears in such a way that their teeth meshes and provides a smooth transmission. For a successful gear power transmission the gears are designed in a way that the velocity of the pitch circles of the two gears remains the same at the time of contact.
If a Gear A (driver) and B (driven) meshes having radius Ra and Rb and angular velocity Wa and Wb then
V= RaWa = RbWb
So Wa/Wb = Rb/Ra = Na/Nb where Na = No. of teeth of driver gear A and Nb is the No. of teeth on the driven gear B.
Explain Stress Strain Graph / Stress Strain Curve for Mild Steel. Describe Stress Strain relationship. What are the units of stress?
Answer: Follow the link: Stress Strain Curve for Mild Steel. Units of Stresses are Pa. Most of the times GPa or Giga Pascal is used to express the units of stress for materials.
What is water jacket?
Answer: Water Jacket is a water filled casing. The water in the water jacket may be circulated by a pump. Water jackets are used for cooling purposes of condensers, water cooled IC engines etc.
What is limiting friction?
Answer: When a body tries to slide over another surface or starts sliding they experience some opposite force from the adjacent surface. Limiting friction is the maximum value of the friction force when a body just starts to slide. There are condition and laws of limiting friction.
Describe the co-efficient of friction formula.
Answer: Co-efficient of friction is denoted by the Greek letter µ. It is the ratio of maximum frictional force to the normal force (the force that pushes the object towards the other surface)
µ = F/R , where F = Friction Force and R= Normal force.
Write short notes on lathe chucks.
Answer: Chucks are the work holding devices for Lathes. Chucks are mechanical vises which hold the workpiece and transfer rotational motion of the drive motor to the work piece. Chucks are adjustable and can be of two basic types.
3 Jaw Self Centering Chuck and 4 Jaw Independent Chuck. Please Click on the image to have a clear idea of the lathe chucks.
What is the value of modulus of elasticity of steel?
Answer: Up to elastic limit strain is proportional to stress. The ratio of stress to strain is known as modulus of elasticity or young’s modulus of elasticity. Modulus of elasticity for steel is measured 210 GPa.
What is the bending moment equation for simple bending of beams/ Describe bending moment formula?
Answer: σ = MC/I = E/R
Here, M = bending moment, I = Moment of inertia, C = Distance of extreme fiber from the neutral axis. E= Modulus of elasticity, R = Radius of curvature, σ = Stress
What is the effective length of column?
Answer: Click the image for a clear view and the end conditions. For Pinned ends L= Le , For both ends fixed Le= 0.5L , For one end fixed one end pinned Le = 0.7L, for One end free and other end fixed Le = 2L.
What does CNC stand for? CNC Meaning / CNC definition.
Answer: CNC stands for Computer Numerical Controls.
Numeric Controls creates the automation of the machine tools. If computer program is used to make the automation then the system is called CNC system. In modern times Computer Aided designs (CADs) are used in the CNC machines for precise operation.
How the value of gear train is measured?
Answer: The mechanical system which engages two or more gears in such a way that their teeth meshes and provides a smooth transmission. For a successful gear power transmission the gears are designed in a way that the velocity of the pitch circles of the two gears remains the same at the time of contact.
If a Gear A (driver) and B (driven) meshes having radius Ra and Rb and angular velocity Wa and Wb then
V= RaWa = RbWb
So Wa/Wb = Rb/Ra = Na/Nb where Na = No. of teeth of driver gear A and Nb is the No. of teeth on the driven gear B.
Explain Stress Strain Graph / Stress Strain Curve for Mild Steel. Describe Stress Strain relationship. What are the units of stress?
Answer: Follow the link: Stress Strain Curve for Mild Steel. Units of Stresses are Pa. Most of the times GPa or Giga Pascal is used to express the units of stress for materials.
What is water jacket?
Answer: Water Jacket is a water filled casing. The water in the water jacket may be circulated by a pump. Water jackets are used for cooling purposes of condensers, water cooled IC engines etc.
What is limiting friction?
Answer: When a body tries to slide over another surface or starts sliding they experience some opposite force from the adjacent surface. Limiting friction is the maximum value of the friction force when a body just starts to slide. There are condition and laws of limiting friction.
Describe the co-efficient of friction formula.
Answer: Co-efficient of friction is denoted by the Greek letter µ. It is the ratio of maximum frictional force to the normal force (the force that pushes the object towards the other surface)
µ = F/R , where F = Friction Force and R= Normal force.
Write short notes on lathe chucks.
Answer: Chucks are the work holding devices for Lathes. Chucks are mechanical vises which hold the workpiece and transfer rotational motion of the drive motor to the work piece. Chucks are adjustable and can be of two basic types.
3 Jaw Self Centering Chuck and 4 Jaw Independent Chuck. Please Click on the image to have a clear idea of the lathe chucks.
What is the value of modulus of elasticity of steel?
Answer: Up to elastic limit strain is proportional to stress. The ratio of stress to strain is known as modulus of elasticity or young’s modulus of elasticity. Modulus of elasticity for steel is measured 210 GPa.
What is the bending moment equation for simple bending of beams/ Describe bending moment formula?
Answer: σ = MC/I = E/R
Here, M = bending moment, I = Moment of inertia, C = Distance of extreme fiber from the neutral axis. E= Modulus of elasticity, R = Radius of curvature, σ = Stress
What is the effective length of column?
Answer: Click the image for a clear view and the end conditions. For Pinned ends L= Le , For both ends fixed Le= 0.5L , For one end fixed one end pinned Le = 0.7L, for One end free and other end fixed Le = 2L.
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One reason scientists believed on Theory of Evolution is the anatomical evidence they found which shows resemblance between generations over time. It shows physiological as well as genetic resemblance between our ancestors and current generation. These evidences help us to study the similarities and differences between living beings.
Study of fossils is the biggest example of anatomical evidence which proves the theory of evolution.
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