# Diploma Strength of Materials Important Questions N Scheme

## Diploma Strength of Materials Important Questions N Scheme

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Strength of Materials is considered as one of the toughest subjects in Diploma. Hence we have find out the Diploma strength of materials important questions N scheme and We have added Diploma Strength of Materials Important Questions N Scheme, Diploma Strength of Materials Important Questions for N scheme. You can download the Diploma Strength of Materials Important Questions pdf

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### Diploma Strength of Materials N Scheme important questions

NOTE :

1. The highlighted Questions are asked more than two times in the Board Exam – M Scheme, We Matched the syllabus of M Scheme & N Scheme and Removed M Scheme Questions

2. These Questions are collected from Board Examination Question Papers.

3. The student may practice these questions .

Unit 1,ENGINEERING MATERIALS

3 marks Questions

1. Define angle of friction.
2. Explain cone of friction.
3. Differentiate between static friction & dynamic friction.
4. Distinguish between force of friction and limiting force of friction.
5. Define co-efficient of friction.
6. Define temperature creep.
7. Distinguish between linear strain and lateral strain
8. Define proof resilience and modulus of resilience.
9. Define fatigue strength
10. What is meant by elastic limit,
11. Distinguish between factor of safety and load factor.
12. Define bulk modulus.
13. Define creep.
14. Define hardness and list its characteristics..
16. Define factor of safety.
17. Define  limit of proportionality

7 / 14 marks questions

1. A steel bar of 25mm diameter and a length of 1m is subjected to a pull of 25kN. If E=2×10^5 N/mm^2, find the elongation, decrease in diameter and increase in the volume of the bar. Take m=4
2. Explain the stress – strain diagram for a mild steel specimen with its salient point parameters.
3. List out the various alloying elements used in steel and explain their major effects.
4. List and explain the various mechanical properties of materials..
5. State the laws of dynamic friction.
6. State the laws of static friction.

Unit – 2 DEFORMATION OF METALS

7 marks questions

1. A circular bar of length 150mm and diameter of 50mm is subjected to an axial pull of 400kN. The extension in length and contraction in diameter were found to be 0.25mm and 0.02mm respectively after loading. Calculate (i) poisson’s ratio (ii) young’s modulus (iii) modulus of rigidity and (iv) bulk modulus.
2. A weight of 1400N is dropped onto a collar at the lower end of a vertical bar 3m long and 25mm diameter. Calculate the height of drop, if the maximum instantaneous stress produced is not to exceed 120N/mm2. Take E=0.2X10^6 N/mm^2.
3. A steel bar of 25mm diameter and a length of 1m is subjected to a pull of 25kN. If E=2×10^5 N/mm^2, find the elongation, decrease in diameter and increase in the volume of the bar. Take m=4
4. Two vertical wires, each 2.5 mm dia and 5m long jointly support a weigh of 2.5kN. one wire is of steel and the other is of different material .If the wires stretch 6mm elastically, find the load taken by each and the value of young’s modulus for the second wire.the young’s modulus od the steel wire is 2×10^5 N/mm^2
5. Explain the stress – strain diagram for a mild steel specimen with its salient point parameters.
6. A bar of steel 28mm diameter and 250mm long is subjected to an axial load of 80kN. It is found that the diameter has contracted by 1/240mm. if the modulus of rigidity is 0.8 x 10^5 N/mm^2. Calculate (i) poisson’s ratio (ii) bulk modulus (iii) youngs modulus.
7. State and explain the three types of elastic constants.
8. A mild steel specimen 25mm rod diameter was subjected to an axial pull of 100 kN. An extension of 0.25mm was noted on a gauge length of 300 mm and a decrease in diameter of 0.00595 mm was observed. Find the values of poisson’s ratio and young’s modulus of the material.
9. A reinforced concrete column 300mm x 450mm has 6 number of 25mm diameter steel bar. Calculate the safe load for the column, if the allowable stress in concrete is 5N/mm^2 and E steel = 15E Concrete.
10. The modulus of rigidity of a metal is 0.4×10^5 N/mm^2. A 10mm diameter of the metal is subjected to an axial load of 4.9kN. the change in diameter is found to be 1.95×10^-3 mm. calculate the poisson’s ratio, young’s modulus and bulk modulus.

UNIT – 3, GEOMETRICAL PROPERTIES OF SECTIONS AND THIN SHELLS.

3 marks questions

1. Define center of gravity
2. Define moment of inertia
3. Distinguish between thin and thick cylinders.
4. Define centroid.
5. State parallel axis theorem.
6. A boiler 2.8m diameter is subjected to a steam pressure of 0.68N/mm^2. Find the hoop stress and longitudinal stress, if the thickness of the boiler plate is 10mm.
7. State perpendicular axis theorem.
8. Derive moment of inertia for rectangular area.
9. Define neutral axis.
10. Distinguish between centre of gravity and centroid.
11. List out the stresses, induced in thin cylindrical shells
12. What is centroidal axis and axis of reference?
13. Define thin cylindrical shell.
14. A steel penstock of 1.5m diameter and 15mm thick is subjected to an internal pressure of 15bar. Calculate the hoop stress and longitudinal stress at the bottom of the penstock.

14 marks questions.

1. An angle section is of 100mm wide and 120mm deep overall. Both the flanges of the angle are 10mm thick. Determine the moment of inertia about the centroidal axes X – X and Y – Y.
2. A spherical shell of 1m internal diameter and 5mm thick is filled with a liquid under pressure until its volume increase by 0.2×10^6 mm^3. Determine the pressure exerted by the liquid on the shell. Take E=2×10^5 N/mm^2 and 1/m = 0.3.
3. Find Ixx, Iyy, Kxx and Kyy of a ‘T’ section with flange 150mm x 20mm and web 100mm x 20mm.
4. Calculate the increase in volume of a boiler shell 3m long and 1.5m in diameter when subjected to an internal pressure of 2N/mm^2. The thickness is such that the maximum tensile stress is not to exceed 30N/mm^2. Take E=2.1×10^5 N/mm^2 and 1/m=0.28. also calculate the changes in diameter and length.
5. An I-section has the top flange 100mm x 15mm, web 150mm x 20mm and the bottom flange 180mm x 30mm, calculate Ixx, Iyy and also radius of gyration about the centroid axes.
6. A cylinder shell 3m long 500mm in diameter is made up of 20mm thick plate. If the cylinder shell is subjected to an internal pressure of 5N/mm^2, find the resulting hoop stress, longitudinal stress, change in length and change in volume. Take E=2×10^5 N/mm^2 and 1/m = 0.3.
7. A long steel tube 70mm internal diameter and wall thickness 2.5mm has closed ends and subjected to an internal pressure of 10N/mm^2. Calculate the magnitude of hoop stress and longitudinal stress setup in the tube. If the efficiency of the longitudinal joint is 805, state the stress which is affected and what is its revised value?
8. Find the centeroid of an I section having top flange 150mm x 25mm, Web 160mm x 25mm and bottom flange 200mm x 25mm
9. Determine the change in diameter and change in volume of spherical shell 2m in diameter and 12mm thick subjected to an internal pressure of 2 N/mm^2. Assume E=2×10 N/mm^2 and poisson’s ratio = 0.25.
10. Find Ixx and Iyy of an angle section having flange of 100mm x 10mm size and web of 100mm x 10mm thick.
11. A spherical shell of 1.5m diameter and wall thickness of 10 mm. determine the change in diameter and increase in volume when it is subjected to an internal pressure of 2N/mm^2. Take E= 2×10^5 N/mm^2, 1/m = 0.3

Unit 4 – THEORY OF TORSION AND SPRINGS

3 marks questions.

1. Define polar modulus.
2. Write down the advantages of hollow shafts over solid shafts.
3. A closely coiled helical spring made of steel sire of 10 mm diameter has 10 coils of 120mm mean diameter. Calculate the deflection of the spring under an axial load of 100N. Take modulus of rigidity as 1.2×10^5 N/mm^2.
4. State the applications of springs.
5. Write down the assumptions made in theory of pure torsion.
6. Write down the various types of springs.
7. Write torsion equation.
8. Define polar modulus for (i) solid shaft (ii) hollow shaft.
9. State the difference between open and closely coiled helical spring.
10. Define stiffness of spring.
11. A closely coiled helical spring has the stiffness of 40N/mm. determine its number of turns, when the diameter of the wire of the spring is 10mm and diameter of the coil is 80mm. take C=0.8 x 10^5 N/mm^2
12. Find the torque transmitted by the solid shaft of diameter 0.4m. the angle of twist is not to exceed 1 degree in a length of 10m. take C = 0.8×10^5 N/mm^2.
13. What is laminated spring? List its applications.

14 marks questions.

1. A hollow shaft having inner diameter 0.6 times the outer diameter is to replace a solid shaft of same material to transmit 550kW at 220 rpm. Calculate the diameters of the hollow and solid shafts. Also calculate the percentage of savings in material. The allowable shear stress is 80N/mm^2.
2. A weigh of 15ON is dropped on to a compression spring with 10 coils of 12mm diameter closely coiled to a mean diameter of 150mm. if the instantaneous contraction is 140mm, calculate the height of drop. Take C = 0.8×10^5 N/mm^2.
3. A solid shaft is transmitting. 100kW power at 180 rpm. If the allowable shear stress is 60N/mm^2, find the necessary diameter for the shaft. The shaft is not to twist more than 1 degree in a length of 3m. take C=80kN/mm^2.
4. Calculate the power transmitted by a shaft of 100mm diameter running at 250 rpm, if the shear stress in the shaft material is not to exceed 75N/mm^2 (5 marks)
5. A closely coiled helical spring made of steel wire of 100mm diameter has 10 coils of 120mm mean diameter. Calculate the deflection under an axial load of 100N and the stiffness of the spring. Take C =1.2 N/mm^2.
6. Hollow circular shaft of 25mm outside diameter and 20mm inside diameter is subjected to a torque of 50Nm. Find the shear stress induced at the outside and inside layer of shaft.
7. A truck weighing 30kN and moving at 5km/hr has to be brought to rest by buffer. Find how many springs each of 18 coils will be required to the energy of motion during a compression of 200mm. the spring is made of 25 mm diameter steel rod coiled to a mean diameter of 240mm. take N=0.84×10^5 N/mm^2.
8. With neat sketches, explain the various types of springs.
9. A solid shaft 20 mm diameter transmits 10kW at 1200 rpm. Calculate the maximum intensity of shear stress induced and the angle of twist in degrees in a length of 1m. if modulus of rigidity for the material of the shaft is 8×10^4 N/mm^2.
10. A truck weighing 20kN and moving at 6km/hr has to be brought to rest by buffer. Find how many springs each of 15 coils will be required to the energy of motion during a compression of 200mm. the spring is made of 25 mm diameter steel rod coiled to a mean diameter of 200mm. take N=0.945 x 10^5 N/mm^2.
11. A hollow shaft of 200mm external diameter, thickness of the metal 200mmm is transmitting power at 80 rpm. Angle of twist in a length 3m was found to be 0.7 degree. Calculate the power transmitted and shear stress developed. Take C=0.8 x 10^5 N/mm^2.
12. Prove the torsion equation.
13. The mean diameter of a closely coiled helical spring is 5 times the diameter of wire. If elongates 8mm under an axial pull of 120N, if the permissible shear stress is 40N/mm^2. Find the size of wire and number of coils in the spring. Take N = 0.8 X 10^5 N/mm^2

Unit,5 – SF AND BM DIAGRAMS OF BEAMS AND THEORY OF BENDING.

3 marks questions

1. Write down the relationship between load, shear force and bending moment.
2. Write down the assumptions made in theory of simple bending.
4. Define shear force and bending moment.
5. Define neutral axis.
6. Write sign conversions for shear force and bending moment.
7. Define section modulus. Write down the expression for rectangular & circular section.
8. Define support. List the various types of loads.
9. What is beam?
10. What is cantilever beam and simply supported beam?
11. What is UDL and UVL?
12. What is sagging moment?
13. What are the types of beams according to the support conditions?

14 marks questions

1. A simply supported beam of span 6m carries three points loads of 30kN, 25kN, and 40kN, at 1m, 3m, and 4.5m respectively from the left support. Draw the SFD and BMD and indicates the maximum value of bending moment.
2. A cantilever beam of span 2m carries a point load of 600N at its free end. If the beam is rectangular section of 100mm wide and 150mm deep, find the maximum bending stress induced. (5 marks)
3. Derive an expression for section modulus of a rectangular section. ( 5marks)
4. A simply supported beam of length 6m carries an udl of 20kN/m throughout its length and a point load of 30kN at 2m from the right support. Draw cantilever aw the SFD and BMD. Find the position and magnitude of maximum bending moment.
5. A cantilever beam of 4m long carries an udl of 20kN/m over half of its length from the free end. Draw the SF and BM diagrams (5 marks)
6. A rectangular beam of 300mm deep is simply supported over a span of 4m. what udl the beam may carry, if the bending stress is not to exceed 120N/mm^2 take l= 8×10^6 mm^4.
7. A beam is freely supported over a span of 8m. it carries point load of 3kN at 2m from the left hand support and an udl of 2kN/m run from the center to the right hand support. Construct SFD and BMD.
8. A cast iron water main 450mm bore and 20mm thick is supported at intervals of 6m. assuming each span as simply supported, find the maximum stress in metal when (i)pipe is running full and (ii) the pipe is empty. Specific weight of cast iron is 70kN/m^3 and specific weight of water is 9.81 kN/m^3.
9. Write down the expression for section modulus of rectangular and circular beam.
10. A simply supported beam of span 10m carries an udl of 20kN/m over the left half of the span and a point load of 30kN at the mid span. Draw SFD and BMD. Find also the position and magnitude of maximum bending moment.
11. Draw the SFD and BMD for a simply supported beam subjected to a point load ‘W’ at its mid point.
12. A wooden beam of rectangular section 100mm x 200mm is simply supported over a span of 6m. determine the UDL it may carry, if the bending stress is not to exceed 7.5 N/mm^2. Estimate the concentrated load it may carry at the center of the beam with the same permissible stress.
13. A simply supported horizontal beam of span 5m long concentrated loads of 70kN, 90kN, and 50kN, at 1m, 3m, 4m and 4.5m respectively from the left hand support. Find the reactions ans Draw the SFD and BMD.
14. A test beam of aquare section 25mm x 25 mm is broken by a transverse load of 750N applied at the center of the span of 1m. using the factor of safety of 4. Calculate the safe udl for a beam of 120mm width and 300mm deep, freely supported over a span of 5m 