Machine Design for Board Exam PDF

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PART 1: MACHINE DESIGN SHORT PROBLEMSSTRENGTH OF MATERIALS A horizontal cantilever beam, 16 ft long is subjected to a load of 500 lb located to its center. The dimensionofthebeamis2x4inchesrespectively=100lb/ft,finditsflexularstress:AA. 3150psi B. 2912psi C. 4510psi D. 5663psi A 12 m simply supporte...

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PART 1: MACHINE DESIGN SHORT PROBLEMS STRENGTH OF MATERIALS 1.

A horizontal cantilever beam, 16 ft long is subjected to a load of 500 lb located to its center. The dimension of the beam is 2 x 4 inches respectively. w = 100 lb/ft, find its flexular stress. Answer: A A. 3150 psi B. 2912 psi C. 4510 psi D. 5663 psi

2.

A 12 m simply supported beam with 30 KN load at the center has a maximum deflection of: (EI = 6000 KN.m2). Answer: D A. 150 mm B. 160 mm C. 170 mm D. 180 mm

3.

A 10 m simply supported beam with 25 KN load 3m from the left end has a maximum slope at the left end: (EI = 8000 Kn.m2). Answer: C A. 0.0056 rad B. 0.0765 rad C. 0.0186 rad D. 0.1823 rad

4.

A 10 m simply supported beam has a uniform load of 2 KN/m extended from left end to 4 m and has a concentrated load of 10 KN, 2 m from the right end. Find the maximum moment at the 10 KN concentrated load. (EI = 10,000 KN.m2). Answer: A A. 19.20 KN.m B. 26.34 KN.m C. 23.45 KN.m D. 12.34 KN.m

5.

A 10 m simply supported beam with uniform load of 3 KN/m from right end to left end has a maximum deflection of: (EI = 12,000 Kn.m2). Answer: B A. 43.23 mm B. 32.55 mm C. 54.23 mm D. 36.45 mm

6.

A 8 m simply supported beam has a uniform load of 2 KN/m from left end to right end and concentrated load of 10 KN at the center has a maximum deflection of: (EI = 5,000 Kn.m 2). Answer: B A. 12.34 mm B. 42.66 mm C. 21.33 mm D. 34.34 mm

7.

A 10 m cantilever beam has a concentrated load of 10 KN/m at the free end. Find the maximum deflection of the beam. (EI = 7,000 Kn.m2). Answer: A A. 476.20 mm B. 342.34 mm C. 544.34 mm D. 764.44 mm

8.

A 14 m cantilever beam has a concentrated load of 25 KN/m at the mid-span. Find the maximum slope of the beam. (EI = 9,000 Kn.m2). Answer: B A. 0.00234 rad B. 0.068 rad C. 1.23 rad D. 0.123 rad

9.

A 10 m cantilever beam has a uniform load of 2.5 KN/m from left to right end. Find the maximum deflection of the beam. (EI = 11,000 Kn.m2). Answer: D A. 423.45 mm B. 198.23 mm C. 323.45 mm D. 284.10 mm

10. A 10 m cantilever beam has a uniform load of 2 KN/m from left to right end and with concentrated load of 8 KN at the center. Find the maximum slope of the beam. (EI = 13,000 Kn.m 2). Answer: C A. 0.011 rad B. 0.022 rad C. 0.033 rad D. 0.044 rad 11.

A 14 m cantilever beam has a load of 16 KN, 6 m from the fixed end. Find the maximum slope of the beam. (EI = 6,000 Kn.m2). Answer: B A. 0.183 rad B. 0.048 rad C. 0.863 rad D. 0.064 rad

12. A 12 m cantilever beam has a uniform load of 1.5 KN/m extended from fixed end up to 4 m and a concentrated load of 8 KN at the free end. Find the maximum slope of the beam. (EI = 8,000 Kn.m2). Answer: A A. 0.126 rad B. 0.234 rad C. 0.654 rad D. 0.345 rad 13. A 10 m simply supported beam has a triangular load from zero at the left end to a maximum of 10 KN/m at the right end. Find the maximum deflection of the beam. (EI = 10,000 Kn.m2). Answer: B A. 54.24 mm B. 65.10 mm C. 84.67 mm D. 76.56 mm

14. An 8 m cantilever beam has a triangular load from left end to a maximum of 12 KN/m at the fixed end. What is the maximum deflection of the beam? (EI = 12,000 Kn.m2). Answer: A A. 136.53 mm B. 145.34 mm C. 165.34 mm D. 154.34 mm 15. A 12 m restrained beams with two end fixed has a concentrated load of 15 KN at the center. Find the maximum deflection of the beam. (EI = 7,000 Kn.m2). Answer: C A. 8.45 mm B. 34.23 mm C. 19.28 mm D. 24.67 mm 16. A 15 m restrained beams with two end fixed has a uniform load of 3 KN/m, find the maximum deflection of the beam. (EI = 9,000 Kn.m2). Answer: D A. 56.34 mm B. 23.56 mm C. 34.56 mm D. 43.94 mm 17. A vertical load of 400 N acts at the end of a horizontal rectangular cantilever beam 2 m long and 25 mm wide. If the allowable bending stress is 130 Mpa, find the depth of the beam. Answer: B A. 23.45 mm B. 38.43 mm C. 56.43 mm D. 45.34 mm 18. A simply supported beam is 50 mm by 200 mm in cross-section and 4 m long. If the flexular stress is not to exceed 8.3 Mpa, find the maximum mid-span concentrated load. Answer: A A. 2.77 KN B. 6.34 KN C. 3.45 KN D. 4.34 KN 19. A simple wooden beam, 50 mm wide by 250 mm deep and 7.5 m long has a maximum deflection of 102 mm under a uniform load “w”. E = 12,411 Mpa. A. What is the uniform load, w. Answer: 2KN/m B. What is the slope? Answer: 0.0435 rad C. What is the maximum moment? Answer: 14 KN.m D. What is the maximum shear? Answer: 7.5 KN E. What is the flexular stress? Answer: 26.880 Mpa F. What is the shearing stress? Answer: 900 Kpa 20. A simply supported beam having a span of 6 m carries two concentrated loads of 80 KN at its middle thirds. Compute the deflection at the mid-span due to this load. Let EI = 30,670 x 10 9 N.mm2. Answer: B A. 18 mm B. 20 mm C. 24 mm D. 30 mm

21. A cantilever beam having a span of 6 m, carries a triangular load of 20 KN/m at its fixed end to zero at the free end of the beam. Determine the deflection at the free end of the beam if EI = 50 x 10 12 N.mm2. Answer: A A. 17.28 mm B. 16.48 mm C. 15.62 mm D. 12.63 mm 22. A simply supported rectangular beam 50 mm wide by 100 mm deep carries a uniform load 1200 N/m over its entire length. What is the maximum length of the beam if the flexular stress is limited to 20 Mpa. Answer: A A. 3.33 m B. 4.25 m C. 5.2 m D. 6.0 m 23. A simply supported beam having a span of 20 m carries a concentrated load of 10 KN at a distance of 5 m from the left support and a counter clockwise couple of 6KN.m acting 3 m from the right support. The maximum moment due to this load is: Answer: A A. 39 KN. m B. 43 KN. m C. 36 KN. m D. 48 KN. m 24. A cantilever beam having a span of 4 m carries a concentrated load of 50 KN at the free end. What is the flexular rigidity if the beam deflects 29.63 mm at is free end. Answer: A A. 36,000 KN. m2 B. 42,000 KN. m2 C. 24,800 KN. m2 D. 54,200 KN. m2 25. A restrained beam carries a triangular load which increases from zero to 30 KN/m from A to B having a span of 4 m. Determine the moment A. Answer: D A. 12 KN. m B. 24 KN. m C. 18 KN. m D. 16 KN. m 26. A cantilever beam 3 m long carries a concentrated load of 35 KN at its free end. The material is structural steel and the maximum bending stress is not to exceed 125 Mpa. Determine the required diameter of the bar if it is circular. Answer: A A. 204.5 mm B. 188.6 mm C. 164.6 mm D. 179.2 mm

27. A steel beam 2 m in length is simply supported at each end and carries a concentrated load of 100 KN acting 0.5 m from one of the supports. Determine the maximum bending stress set-up in the beam if the cross-section is rectangular, 100 mm wide by 150 mm deep. Answer: A A. 100 Mpa B. 120 Mpa C. 97 Mpa D. 150 Mpa 28. A beam made of titanium has a yield point of 850 Mpa. The beam has 25 mm x 50 mm rectangular cross-section and bends about an axis paralles to the 25 mm face. If the maximum bending stress is 650 Mpa, find the corresponding bending moment. Answer: A A. 6.8 KN.m B. 8.4 KN.m C. 4.5 KN.m D. 8.4 KN.m 29. A restrained beam having a span of 6 m carries a uniform load of 50 N/m throughout its span. If E = 200,000 Mpa, I = 6080 x 106 mm4, determine the deflection at the mid-span. Answer: A A. 0.14 mm B. 0.25 mm C. 0.36 mm D. 0.48 mm MECHANICS 1.

A car travels with an initial velocity of 10 m/s or 36 km/hr. If it is decelerating at the rate of 3 m/s 2, how far, in meters, does it travel before stopping? Answer: A A. 17 B. 21 C. 19 D. 15

2.

A block weighing 56 lbs rest on horizontal surface. The force needed to move along the surface is 20 lbs. determine the coefficient of friction. Answer: C A. 0.0 B. 0.112 C. 0.36 D. 0.28

3.

A baseball is thrown straight upward with a velocity of 20 m/s. Compute for the time elapse for the baseball to return. Assume for a zero drag. Answer: D A. 1.84 B. 2.21 C. 2.50 D. 2.04

4.

A 114 km/s speed is projected vertically how long will it take to go back to its initial position. Answer: A A. 6.45 hrs B. 1.23 hrs C. 7.23 hrs D. 8.45 hrs

5.

An occupant moves toward the center of a merry go around at 6 m/s. If the merry go around rotates at 6 rpm, compute the acceleration component of the occupant normal to the radius. Answer: D A. 6.79 m/s2 B. 8.29 m/s2 C. 7.54 m/s2 D. 3.77 m/s2

6.

A wheel accelerates from rest with a = 5 rad/sec.sec. Compute how many revolutions are made in 4 seconds. Answer: B A. 5.71 rev B. 6.36 rev C. 7 rev D. 20 rev

7.

What minimum distance can a truck slide on a horizontal asphalt road if it is travelling at 25 m/s. The coefficient of sliding friction between asphalt and rubber is at 0.6. The weight of the truck is 8500 kg. Answer: C A. 44.9 B. 58.5 C. 53.2 D. 63.8

8.

A liquid full is to be rotated in the vertical plane. What minimum angular velocity in radians/sec is needed to keep the liquid not spilling if the rotating arm is 1.2 meters? Answer: D A. 2.26 B. 25.6 C. 3.16 D. 2.86

9.

Compute the speed a satellite to orbit the earth at an elevation of 100 km. Earth’s radius is at 6400 km. Assume no change in gravity with the elevation. Answer: D A. 6320 m/s B. 7120 m/s C. 8740 m/s D. 7985 m/s

10.

An elevator weighing 2000 lbs is moving vertically upward with an acceleration of 3 ft/s2. A man standing in said elevator weighs 180 lbs.Compute the tension in the supporting cable under this condition. Answer: D A. 2180 lbs B. 2191 lbs C. 1820 lbs D. 2383 lbs

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The capsule orbits the earth 180 km above the surface. In what velocity in m/s necessary for a circular orbit to consider the earth radius at 6400 km and 9.2 m/s2? Answer: C A. 8864 B. 7016 C. 7780 D. 8058 A truck skids to a stop 60 m after the application of the brakes while travelling at 90 km/hr. What is its acceleration in m/sec2? Answer: A A. -5.21 m/s2 B. -7.06 C. 6.36 D. 5.76

13.

A drop hammer of 1 ton dead weight capacity is propelled downward by a 12 in diameter cylinder. At 100 psi air pressure, what is the impact velocity if the stroke is 28 inches? Answer: B A. 63.2 fps B. 31.6 C. 15.8 D. 47.4

14.

A flywheel rotates at 120 rpm or 12.57 rad/sec slowed down to 102 rpm or 10.68 rad/sec during the punching operation that requires ¾ second of the punching portion of the cycle. Compute the angular acceleration of the flywheel in rad/sec 2. Answer: A A. -2.52 rad/s2 B. -2.75 rad/s2 C. 3.15 rad/s2 D. 2.22 rad/s2

15.

A 2-ton weight is lowered at a constant acceleration of 2 ft/s2. What is the cable stress? Answer: C A. 4344.34 lb B. 5344.56 lb C. 3751.55 lb D. 6356.24 lb

16.

The speedometer of a vehicle changes from 20 km/hr to 80 km/hr in 10 seconds. Find the acceleration for this period in m/s2. Answer: A A.1.67 B. 6.34 C. 2.34 D. 8.45

17.

A car changes accelerates its speed from 20 m/s to 50 m/s in 10 sec. Find the distance travelled during the period of acceleration. Answer: A A. 350 m B. 500 m C. 400 m D. 600 m

18.

A box sliding on a floor has a frictional resistance of 100 N. If the coefficient of friction is 0.3, find the weight of the box. Answer: D A. 222.22 N B. 111.11 N C. 444.44 N D. 333.33 N

19.

An object dropped on a gravity travels 300 m after how many seconds? Answer: C A. 5.34 sec B. 6.34 sec C. 7.82 sec D. 10.23 sec

20.

An object is projected upward at the rate of 40 m/s. How high will the object rise? Answer: D A. 54.34 m B. 76.45 m C. 65.34 m D. 81.55 m

21.

A stone is projected upward from the ground travels a maximum height of 50 m. Find the velocity of stone when it returns to the ground. Answer: A A. 31.32 m/sec B. 54.34 m/sec C. 43.23 m/sec D. 23.45 m/sec

22.

An object is projected upward at the rate of 45 m/s at 30 0 from the horizontal. Find the maximum range of projectile. Answer: A A. 178.77 m B. 165.34 m C. 189.34 m D. 109.34 m

23.

A capsule orbits the earth at the rate of 6000 m/s. If the radius of earth is 3000 km, find the height of capsule from the surface of the earth. Answer: B A. 435.66 m B. 669.72 m C. 543.23 m D. 785.45 m

24.

A car that travels 100 mph reduces its speed 50 mph in 30 seconds. Find the distance travelled by the car until it stops. Answer: A A. 4402.10 m B. 3452.34 m C. 5434.56 m D. 6456.35 m

25.

A car travelling at 40 m/s in a radius of 1000 m will have a banking angle of:. Answer: C A. 7.340 B. 183.40 C. 9.360 D. 12.30 MACHINE SHOP

1.

Determine the time in seconds, to saw a rectangular magnesium bar 5 in wide and 2 in thick if the length of cut is 5 in. The power hacksaw does 120 strokes/min and the feed/stroke is 0.127 mm. Answer: B A. 189 B. 500 C. 99 D. 20

2.

In an Oxy-Acetylene manual welding method, to weld a 3 ½ ft long seam in a 0.375” thick steel plate at a consumption rate of 9 ft3/ft for oxygen and 7 ft3/ft for acetylene. Compute for the total combined gas consumption in ft3. Answer: C A. 189 B. 500 C. 99 D. 20

3.

Compute for the drill penetration in in/min when a drill turns at 1200 rpm and the feed of 0.005 in/rev. Material is steel. Answer: D A. 1.8 B. 3.6 C. 12 D. 6

4.

What is the value in degrees of 1 radian? Answer: C A. 57.490 B. 57.940 C. 57.290 D. 57.920

5.

Compute the manual cutting time in minutes, of steel plate 4 ft by 8 ft by 2.5 cm thick with a hand cutting speed of 3.8 to 4 mm/sec, cutting lengthwise Answer: A A. 10 B. 1.81 C. 0.38 D. 8.16

6.

Compute the cutting speed in fpm of a workpiece with 2 inches diameter and running at 100 rpm. Answer: A A. 52 B. 62 C. 25 D. 26

7.

Compute the cutting speed in fpm of a workpiece with 2 inches diameter and turning at 100 rpm. Answer: D A. 72 B. 102 C. 62 D. 52

8.

Determine the average time to cut by automatic oxyacetylene (machine) crosswise a 4 ft x 8 ft x 4 in thick steel plate. Answer: B A. 6.85 B. 318 C. 10 D. 360

9.

Calculate the rpm for machining a cast iron workpiece 6 inches in diameter. The lowest cutting speed for cast iron is 50 fpm. Answer: C A. 35.3 B. 43.3 C. 33.3 D. 53.32

10. With the arc welding rate of 18 in/min, how long will it take to weld ½ in thick plate by 3 feet long seam? Answer: C A. 3 min B. 1.5 min C. 2 min D. 4 min 11.

How long will it take to mill a ¾” by 2” long keyway in a 3” diameter shafting with a 24 tooth cutter turning at 100 rpm and a 0.005” feed/tooth? Answer: B A. 0.136 min B. 0.166 min C. 0.196 min D. 0.106 min

12. How long will it take to saw a rectangular piece of aluminum plate 8 in wide and 1 ½ in thick if the length of the cut is 8 in, the power hacksaw makes 120 rev/min and average feed per stroke is 0.0060 in? Answer: C A. 13.11 B. 14.01 C. 11.11 D. 12.03 13. Using oxy-acetylene welding method to weld a 3 ft long seam in a 3/8 in thick plate at a consumption rate of 9 ft3/ft of weld for oxygen and 7 ft 3/ft for acetylene. What is the total combined gas consumption in ft3? Answer: C A. 51 B. 45 C. 48 D. 55

14. A grinding wheel rotates 1750 rpm and has a surface speed of 2290 ft/min. Find the diameter of the wheel in inches. Answer: B A. 3 in B. 5 in C. 4 in D. 6 in 15. To facilitate the milling (roughing) work of a cast steel material using a 1 ½ inch diameter cutter choose between the two available stock. Find the speed of the cutter in rpm. –high speed steel cutter with a cutting speed of 50 fpm- carbide tipped cutter with cutting speed of 200 fpm.. Answer: B A. 389 B. 509 C. 572 D. 412 16. A piston reciprocates 100 times per minute (single stroke). The length of the stroke is 6 in. What is the average wristpin velocity in ft/min? Answer: A A. 50 ft/min B. 100 ft/min C. 75 ft/min D. 125 ft/min 17. A workpiece turning at 300 rpm has a tangential speed of 15 ft/s. Find the diameter of the workpiece. Answer: A A. 11.46 in B. 15.23 in C. 13.23 in D. 17.34 in 18. A workpiece turning at 20 rad/sec has diameter of 4 in. Find the peripheral speed of workpiece. Answer: B A. 1.23 fps B. 3.33 fps C. 5.23 fps D. 7.34 fps 19. Two plates 4 ft x 8 ft plate ½ in thick is to be joined lengthwise. A welding machine to be used has a welding rate of 20 in/min. How long will it take to join the plates? Answer: C A. 7.34 min B. 1.23 min C. 4.80 min D. 6.45 min 20. A 10 ft long seam can be weld in 10 min. the welding rate is: Answer: B A. 8 in/min B. 12 in/min C. 10 in/min D. 14 in/min

21. A seam can be weld in 3 min. If the welding rate is 15 in/min, find the length of the seam. Answer: D A. 20 in B. 30 in C. 25 in D. 45 in 22. How long will it take to mill ½“by 1.5“long keyway by means of 25 teeth cutter turning at 120 rpm and 0.008” feed/tooth. Answer: D A. 1.23 sec B. 6.34 sec C. 4.23 sec D. 3.75 sec 23. A 5 in long keyway is to be mill at the rate of 0.2 in/min. How long will it take to mill the keyway? Answer: C A. 20 sec B. 15 sec C. 25 sec D. 30 sec 24. It takes 1 min to mill a ¾” x 4” keyway of a hub by means of a cutter having 30 teeth at 120 rpm. Find the equivalent feed per tooth, in/tooth. Answer: D A. 0.00222 B. 0.00444 C. 0.00333 D. 0.00111 25. How long will it take to cut a rectangular plate 4 ft wide by means of a saw that has a speed of 160 rev/min and an average feed per stroke of 0.009 in? Answer: B A. 22.22 min B. 33.33 min C. 55.55 min D. 44.44 min 26. A 4 ft wide x 8 ft long and ½ in thick steel plate is be cut into 4 equal parts crosswise. If cutting rate is 0.02 in/stroke and saw speed is 110 rpm, how long will it take to do the job? Answer: C A. 53.45 min B. 34.23 min C. 65.45 min D. 67.45 min 27. It takes 5 min to cut a plate 20 ft long by means of a saw having a speed of 250 rpm. What is the average feed per stroke of the saw, in/stroke? Answer: B A. 0.534 B. 0.192 C. 0.745 D. 0.342

28. An oxyacetylene cutter is use to cut a 4 ft x 8 ft steel plate crosswise and divided the whole plate into five equal parts. If the cutting rate is 10 in per minute, how long will it take to cut plates? Answer: A A. 19.20 min B. 13.45 min C. 21.23 min D. 17.34 min 29. Using oxyacetylene welding method to weld a 10 ft long seam in a ½ in thick plate at a consumption rate of 10 ft3/ft oxygen and 8 ft3/ft for acetylene. What is the total gas consumption? Answer: D A. 150 ft3 B. 170 ft3 C. 160 ft3 D. 180 ft3 30. A 24 ft2 lateral surface for a cylindrical tank is to be made by joining 2 ft by 2 ft steel plate to form 6 ft x 4 ft. The consumption rate for both oxygen and nitrogen is 20 ft 3/ft using oxyacetylene welding method. Find total gas consumption needed, ft3? Answer: D A. 250 ft3 B. 470 ft3 C. 440 ft3 D. 280 ft3 31. A 10 ft x 20 ft plate is to be divided into 8 pieces 5 ft x 5 ft steel plate by means of an oxyacetylene cutter that has a cutting rate of 10 in per minute. How long will it takes to do the job? Answer: C A. 50 min B. 70 min C. 60 min D. 80 min

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MACHINE ELEMENTS Two parallel shafts connected by pure rolling turn in the same direction having a speed of 2.75. What is the distance of the shafts if the smaller cylinder is 32 cm in diameter? Answer: D A. 16.67 cm B. 25.25 cm C. 30.25 cm D. 19.25 cm A lineshaft runs at 360 rpm. An 18” pulley on the shaft is belt connected to a 12” pulley on the countershaft. From a 15” pulley on the countershaft, motion is transmitted to the machine. Compute/ check the required diameter of the pulley on the machine to give a spindle speed of 660 rpm. Answer: B A. 16” B. 12 ¼ C. 10 ½ D. 8 ½

A 5 ft diameter pulley is turning at 200 rpm. Find the speed of the pulley mid-way of the center and outer surface of the pulley. Answer: D A. 20.45 ft/s

B. 30.45 ft/s C. 24.34 ft/s D. 26.18 ft/s 4.