ENGINEERING MECHANICS MCQ-: 01

 Q.1 work = force × _______ .

 A. Acceleratio                                                      

 B. Distance                                                           

C. Velocity                                                            

 D. Area                                                              

 Ans-: B

Q.2  The change in momentum produced by the action of a force applied on a the body within an infinitely short interval of time is called ?

 A. Force                                                                  

 B. Velocity                                                              

C. Impulse                                                              

D. Frequency                                                          

Ans-: C 

Q.3 The unit of force in S.I. unit is ?

 A. Kilogram                                                            

B. Dyne                                                                    

C. Watt                                                                   

 D. Newton                                                              

And-: D

Q.4 Effect of a force on a body depends upon the ______.

A. Magnitude                                                         

B. Direction                                                           

C. Position or line of action                                 

D. All of the above                                              

Ans-: D

Q.5 Which of the following is not the unit of the power ?

A. Micron                                                               

B. Light year                                                         

C. Millimetre                                                         

D. Milestone.                                                          

Ans-: D

Q.6 Which of the following is applied when trying to turn a key into a lock ?

A. Lever                                                                 

B. Couple                                                               

C. Moment                                                             

D. Coplaner force                                                

Ans -: B

Q.7 The units of moment of inertia of an area are _____.

A. M^4                                                                    .

B. M^3                                                                     

C. Kg/m^2                                                             

D. Kg/m^2                                                               

Ans-: A     

Q.8 The units of moment of inertia of mass are .

A. Kg m^2                                                             

B. Kg/ m^2                                                             

C. M^3                                                                     

D. M^2 / kg                                                              

And-: A

Q.9 Which of the following is not a vector quantity?

A. Velocity                                                             

B. Weight                                                               

C. Moment                                                           

D. Acceleration                                                     

Ans-: B

Q.10 The motion of a particle from one extremity to the other constitutes half an oscillation and is called  ______.

A. Second pendulum                                         

B. Frequency                                                       

C. Beat                                                                   

D. Travel time                                                       

Ans -: C

     

CUTTING FLUID

                       Cutting  fluid  

The Cutting fluids are used to reduce friction , through lubrication, which is a tribological phenomenon characteristic of the machining processes, and occurs at the contact between workpiece and the tool. Also used to remove heat generated from the cutting zone.

Purpose of cutting fluids-: 

• To cool the tool.
• To cool the workpiece. 
• Reduce the friction .
• Protect the finished surface from the corrosion. 
• Reduce the tool wear.

Restrict thermal distortion. 

Types of cutting fluids -: 

1.  Soluble oil
2. Water
3. Mixed oil
4. Chemical additive oil
5. Solid lubricant etc.

ANGLE PLATE

                     Angle plate   

 An angle plate is a work holding device and is used as a fixture in the metal-working.The angle plates are made of  cast iron and is the used in workshop and laboratories. The right angle plates are casted and roughly machin-ed . The holes are provided in vertical plates in order to relive internal stresses. The angle plates are used to check the right angle of the jobs .

This angle plate open and webbed end is the fabricated under strict supervision of highly experienced and professional quality contro-llers. 

Angle plates also may used to hold the work-piece square to the table during marking out the operations. Angle plates are also availab-le adjustable type which can be used for the workpiece that need to be inclined, usually towards a milling cutter.

SIMPLE HARMONIC MOTION

             Simple harmonic motion

If a body moves in a straight line such that it's acceleration is always directed towards a fixed point and is proportional to its distance from the fixed point, it is said to have"simple harmonic motion".                           

Simple harmonic motion is always oscillator . Periodic motion examples are the motion of the hands of a clock, motion of the wheels of a car etc. Simple harmonic motion examples are the motion of pendulum , motion of the spring etc. 

The time taken by the body for one complete oscillation is called time period ' T ' which is equal to 2π/ω ( ω = angular velocity ).                           The acceleration of a particle moving with simple harmonic motion is equal to the  ω^2y ( y = Distance from the mid point ). The velocity of particle moving with the  simple harmoni motion is -:

 V =  ω √ r^2 - y^2   , r = amplitude                     

The time period of simple pendulum is given by ,                                                                                   T = 2π √ l/g                                                         l = length of pendulum 

The motion of particle from one extremity to the other constitutes half an oscillations and called a beat. If a pendulum executes one beat per second or whose time period is the 2 seconds is called " second pendulum ".

For second pendulum,                                                          T = 2π √ l/g   = 2 

SURFACE PLATE

                           Surface plate

The surface plates are extensively used in the workshop and the laboratories as a refe-rence surface testing for flatness of surface. It is a perfectly true surface made of the cast-iron , granite or glass block and set on bench , stand or table with it's flate surface upward . The top face and its adjacent edges are acc-urately machined and scrapped to form a true flate surface. 

     It is used to check the trueness of the flate surface and to copy the master surface on workpiece. It also provide reference datum plan for different measuring instruments as like - V-block, vernier height gauge, dial com-parator etc.

PATTERN MAKING

                       PATTERN MAKING 

The Pattern is the principle tool during the casting process, it may be define as modle of anything, so constructed then it may be used for forming and the impression called mould in the dome shape. When this mould is filled with the molten metal and the metal is allow to solidify , it form a reproduction of pattern is known as casting . The process of making the pattern is known as pattern making.

Foundary engineering deals with the process of making casting in mould prepared by the metal to mould process of producing casting may be classified into five stages -: 

1. Pattern making                                                  2. Moulding                                                            3. Casting and melting                                          4. Fettling                                                                5. Testing and inspection.                   

Pattern material 

1. Wood -: Wood is the most commonly used material for pattern. it is easy to work and is rapidly available , wood can be cut and also fabricated into the numerous form by bend-ing and curling. It may be preserved with the shell.

2. Metal -: Metal is used when large number of casting are desired for a pattern or when conditions are to serves for wooden pattern.

(a) Cast iron  -: Cast iron is used for some of the highly specialised type of the pattern. It is strong give a smooth surface with  Sharp edges and is resistance to the abrasive action of the sand.

(b) White metal -: It is not generally used for the patterns but it is the best material for the making of five shape.

3. Non-Metal -: 

(a) Brass -: The Brass is normally used in the pattern making perticularly when the metal pattern are small.

(b) Aluminium -: It is the best metal because it melts at a relatively low temperature. It is soft and easy to work.

(c) plastic -: Plastic is not finding their place as a the pattern material because, they don't absorb moisture . They are strong resistance to wear have a very smooth surface. 

(d) Rubber -: Originally it is in liquid form and mould over master pattern or into a die and forming a solid shape.

(e) Wax -: Wax pattern are excellent for the investment casting process, the normal prac-tice of forming wax pattern this to inject the liquid or semi-liquid wax into a straight die.

VERNIER CALIPER

                       Vernier caliper

This is a linear measuring instrument and it is used to measure the dimension to second decimal. The vernier caliper is shown in fig. 

 

Main parts of vernier caliper -: 

1. Main scale A  -: It is the fixed beam scale having a fixed jaw at left end and is graduat-ed in millimetre. This is called a metric scale .

2. Vernier scale B -: It consist of sliding jaw and this scale slides over the main scale A . These scale is also graduated in 10 , 20 and 25 divisions. 

3. Jaw C-:These jaw are used to measure the dimensions such as inner radius of inside of the hollow cylinders. 

4. Jaw D  -: These jaw are used to measure the outside diameter of the object like width, thickness etc.

5. Thumb screw E -: It is provided with the vernier scale and used to lock the position of the vernier scale. 

6. Blade F -: The blade is used for measuring depth of the slots.

Least count -:

( 1 ). If there are 10 divisions on the vernier scale, and the smallest division on the main scale is of 1.0 mm.                                          

Then, Least count                                                  =    Smallest division on main scale                         no. of division on vernier scale                    =      1.0            =  0.1 mm.                                              10 

(2). If there are 25 divisions on vernier scale and the smallest division on the main scale is 0.5 mm. Then ,                     

 Least count =   0.5                =  0.02 mm.                                         25

Procedure -: Fix the jaw on the workpiece and then lock the jaw with the help of thumb screw. Then note the reading on main scale angaist zero on vernier scale.  Count the no. of division on vernier scale which co-insides with a division on main scale. Multiply this number by least count and add to the main scale reading. 

Hence ,                                                                    Total reading   = Reading on the main scale   + ( Least count  × no. of division on vernier scale which co-inside with division on main scale ).