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Mechanical Engineering Questions and Answers June 15, 2021

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Mechanical engneers configuration power-delivering machines, for example, electric generatoris, gas powered motors, and steam and gas turbines, as well as power-utilizing machines, for example, refrigeration and cooling frameworks. Mechanical specialists plan different machines inside structures, like lifts and elevators?

A refrigeration system is designed to cool a space from an initial temperature of 35C to a final temperature of 10C. The system uses R134a as the refrigerant and has a cooling capacity of 10,000 W. The compressor has a power input of 2,500 W. Calculate the coefficient of performance (COP) of the refrigeration system.

Consider the wheelandaxle system shown below. Which of the following expresses the con dition required for the system to be in static equilibrium

A wheel of radius R and negligible mass is mounted on a horizontal frictionless axle so that the wheel is in a vertical plane. Three small objects having masses m, M, and 2 M, respectively, are mounted on the rim of the wheel, as shown. If the system is in static equilibrium, what is the value of m in terms of M

A bridge of length 96 m and mass 30000 kg is supported at each end. A truck of mass 22800 kg is located 59 m from the left end. A 59 m B 96 m What is the force on the bridge at the left point of support The acceleration of gravity is 9.8 ms.
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A 12 m ladder whose weight is 261 N is placed against a smooth vertical wall. A person whose weight is 810 N stands on the ladder a distance 5.1 m up the ladder. The foot of the ladder rests on the floor 3.24 m from the wall. Calculate the force exerted by the wall. Answer in units of N.

If you walk along the top of a fence, why can you balance better if you hold your arms out 1. Your rotational inertia is decreased. 2. Your rotational inertia is increased. 3. Your momentum 4. Your momentum is increased. is decreased.

Add the following sound created by machine 80dB, 78dB, 85dB, 60dB, 65dB, 76dB,

Add the noise of six machines which individually make a noise level of 78, 81, 81, 79, 72, 65, dB respectively.

If three sound sources of SPL 90, 92 and 88 operate simultaneously, determine the total sound pressure level by exact and approximate method.

An octave band analysis was done on an automatic wood lathe in operation. It was found that the octave band sound pressure levels were 93 dB at 250 Hz. 94 dB at 500 Hz. 96 dB at 1000 Hz, 96 dB at 2000 Hz, 94 dB at 4000 Hz and 93 dB at 8000 Hz. What is the total mean square pressure.

Noises at the construction site is contributed by a few construction activities such as piling work 104 dB, Scrapper 93 dB, Bulldozer 94 dB, Mobile Compressor 73 dB, and Mechanical Shovel 76 dB on Aweighting Networks. What is,the overall sound pressure level

In the presence of background noise of 85 dB level, the sound measurements of the operation of three machines independently provided values as 88 dB, 90 dB, 92dB. Determine the overall SPL and average sound pressure level of the three machines working together in the absence of background noise.

The intensity of sound of ordinary conversation is 1.1154 x 10 wattscm. What is its intensity level

The intensity of sound at point A a distance of 10 m from the source is 104 wattsm, while the intensity at point B at 1000 m from the source is 10 wattsm. Calculate the intensities at points A and B in decibel. What is the difference between the intensity levels at these two points

A loudspeaker emits energy equally in all directions at the rate of 1.5 Joulessec. What is the intensity level at a distance of 20 m (Standard intensity level 1016 wattsq cm).

Two sounds differ in intensity levels by 45 db. Calculate how many times the louder sound is more intense than the fainter sound

A projectile is fired at an angle of a with respect to horizontal with an initial veloc ity of u. Derive the expressions for time of flight t and horizontal range R.

If a stone falls past a window 1.5 m high in 1 second, find the height from which the stone fell 2

3m A cricket ball is thrown by a fielder from a height of 3 m at an angle of 40 with hori zontal. The initial velocity gained by the ball is 30 msec. The ball hits the wicket at a height of 0.30 m with respect to the ground. Determine how far was the fielder from the wicket 30 msec 40 0.3 m

Prove that the maximum range can be achieved for a given velocity when angle of projection 45.

A hydraulic press, having working pressure of water as 15MPa exerting a force of 70 KN is required to press material a maximum llize of 800 mm x 1200 mm 800. height, the stroke length is 80 mm. draw the following parts of press i) Design of Ram. ii) Cylinder iii) Pillars iv) Design of glard.

A market survey restricts the max. daily demand to 2 tons. Additionally, the interior of point daily demand for interior point cant exceed more than I tons. that of Reddy exterior point by mone Mifks warts to determine the optimum (best product mix of interior exterions points that maximizes the total daily profit. Formulate the LP model to

For laminar flow of an oil having dynamic. M 1.766 Pas in a 0.3m diameter pipe, the velocity point velocity of 3ms at distribution is parabolic with a maximum the centre of the pipe. Calculate the Shearing stresses at the pipe wall wither from the the flund 50mm Wall from pipe wall.

Two parallel plates kept 0.1m apart have laminar flow of oil bw them with a maximum velocity of 1.5ms. Calculate discharge per metre width, the shear stress at plates, the difference in pressure bw two points 20m apart, the velocity gradient at plater. Take vivosity of oil to be 2.453 Ns0.

Design a square flange pipe joint for pipe of Intoural diameter of internal pressure mm of 8 24MPa, the of 50 tubing pipe subjected to wise, the pipe is made of seamless steel of flange and belt not to exceed 47.5 MPa respectively.

Explain the safety measures of nuclear power plant.

Compare a nuclear power plant with a steam power plant

What are the Advantages and Disadvantages of Nuclear power Plants?

Explain the Comparison between water-tube and fire tube boiler

What are the Factors affecting the selection of a boiler

Explain the steam boiler and its principle.

A voltmeter having a sensitivity of 10 kmV reads 75 V in its 100 V scale when connected across an unknown resistor when the current through the resistor is 1.5 mA. Calculate the percentage error due to loading effect.

What are multi-meters. Explain the term thoroughly.

Find support reactions of the beam, loaded as shown in Fig. 2.50.,10kNm 2m AA 10kNm m 4m 20kNm 8 NB.

Determine the range of values of W that may be supported by a force of 600 N shown in Fig. 4.22. u0.4. Rope is making 1 turn round the pulley. 4 600N O 3.

A hawser (rope) thrown from a ship to a wharf is wrapped two full turns around a caption. The tension in the hawser is 7500 N. By exerting a force 150 N on its free end, a man at shore can just keep the hawser from slipping. Determine (a) u between the rope and the Bollard (b) Tension in the rope that could be resisted by 150 N force, if the

Determine the centroid of a circular sector shown in Fig. d 5 B rd T X

The tongs are used to handle hot steel tubes that are being heat treated in an oil bath Ref. Fig. For a 20 jaw opening, what is the minimum coefficient of static friction between the jaws and the tube that will enable the tongs to grip the tube with out slipping 10 N 10 N (a) 10 N 10

Determine the number of turns of rope to be wound around the trunk of a tree in or der to support a man weighing 600 N in a pan as shown in Fig 10 N. Take 0.3. 2 with a force of Janay 10N 800N 30

Determine the moment of inertia of the shaded area shown in Fig. Given a 4.units and b 3 units. about xaxis. xky d

Determine the moment of inertia of a tri angle about its base. C A B

An angle bracket is supported on a hinge and a roller as shown in Fig. 2.40. Calculate the reactions at the hinge A.

HA . Determine the support reactions for the truss shown in Fig. 2.44. 4m H A 3kN 3kN 44 3kN

Determine the moment of inertia of the shaded area shown in Fig. ( with respect to centroidal yaxis.

A stone is thrown vertically upwards with an initial velocity of 6 msec. It returns to earth in 5 seconds. Determine how high does it go in air

A school is paying 0.12kWh for electric power. To reduce its power bill, the school installs a wind turbine (Fig. 112) with a rated power of 30 kW. If the turbine operates 2200 hours per year at the rated power, determine the amount of electric power gener ated by the wind turbine and the money saved by the school per year.

The fluid velocity along the x axis shown in figure changes from 6 ms at point A to 18 ms at point B. It is also known that the velocity is a linear function of distance along the streamline. Determine the acceleration at points A, B, and C. Assume steady flow. V 6 ms A 0.05 m C 0.1 m V 18 ms B

A nozzle is designed to accelerate the fluid from V to V in a linear fashion. That is, V ax b, where a and b are constants. The flow is constant with V 10 ms at x 0 and V 25 ms at x 1. (a) Determine the local acceleration, the convective acceleration, and the acceleration at points (1) and (2). (b) Repeat Prob. (a) with the assumption that

Water flows steadily through the funnel shown in figure. Throughout most of the funnel the flow is approximately radial (along rays from 0) with a velocity of V cr, where r is the radial coordinate and c is a constant. If the velocity is 0.4 ms when r0.1 m, determine the acceleration at points A and B. 1) From the equation of acceleration in the

Air flows from a pipe into the region between a circular disk and a cone as shown in figure. The fluid velocity in the gap between the disk and the cone is closely approximated by V VORr, where R is the radius of the disk, r is the radial coordinate, and V is the fluid velocity at the edge of the disk. Determine the acceleration for r0.5 and 2 ft

Water is squirted from a syringe with a speed of V 5 ms by pushing in the plunger with a speed of Vp 0.03 ms as shown in figure. The surface of the deforming control volume consists of the sides and end of the cylinder and the end of the plunger. The system consists of the water in the syringe at t0 when the plunger is at section (1) as shown.

A turboprop engine operates at an altitude of 3000 meters above mean sea level and an aircraft speed of 525 kmph. The data for the engine is given below, 0.875 0.790 Inlet diffuser efficiency Compressor efficiency Velocity of air at compressor entry 90 ms Temperature rise through the compressor 230C Properties of air y 1.4, cp 1.005 kJkg K

The diameter of the propeller of an aircraft is 2.5m It flies at a speed of 500 kmph at an altitude of 8000m. For a flight to jet speed ratio of 0.75 determine (a) the flow rate of air through the propeller, (b) thrust produced, (c) Specific thrust, (d) specific impulse and (e) the thrust power.

An aircraft flies at 960 kmph. One of its turbojet engines takes in 40 kgs of air and expands the gases to the ambient pressure. The airfuel ratio is 50 and the lower calorific value of the fuel is 43 MJkg. For maximum thrust power determine (a) jet velocity (b) thrust (c) specific thrust (d) thrust power (e) propulsive, thermal and overall

A turbojet engine propels an aircraft at a Mach number of 0.8 in level flight at an altitude of 10 km. The data for the engine is given below.,Stagnation temperature at the turbine inlet 1200K Stagnation temperature rise through the compressor 175K Calorific value of the fuel43MJkg, Compressor efficiency 0.75 Combustion chamber efficiency 0.975

A ramjet engine operates at M1.5 at a altitude of 6500m. The diameter of the inlet diffuser at entry is 50 cm and the stagnation temperature at the nozzle entry is 1600K. The calorific value of the fuel used is 40 MJkg. the properties of the combustion gases are same as those of air (Y1.4, R287 JKg K.. The velocity of air at the diffuser exit is

A turbo jet engine takes in 50 kgsec of air and propels an aircraft with uniform flight speed 880 kmhr. Isentrophic enthalphy change for nozzle is 188 kjkg and its velocity coefficient is 0.96. the fuel air ratio is 1.2. combustion efficiency is 95, calorific value of fuel is 44000 kjkg. find out, i. ii. iii. iv. Thermal efficiency of the engine

A turbo jet has a speed of 750 kmhr while flying at an altitude of 10000m. the 11 propulsive efficiency of the jet is 50 and the overall efficiency of the turbine plant is 16. The density of the air at 10000m altitude is 0.173 kgm. the drag on the plane is 6250 N. calorific value of the fuel is 48000 kjkg. Calculate, i. Absolute velocity of the

For a turbo jet with a flight velocity of 800 kmh at an ambient of 60 kPa, the properties of gas entering the nozzle are 300 kPa and 200C. The mass flow rate of air is 20kgsec. assuming air (Y1.4 and R287 Jkg) as working fluid, find a) thrust developed, b) thrust power and c) propulsive efficiency.

The diameter of the propeller of an aircraft is 2.5 m. it flies at a speed of 500 kmph at an altitude of 8000 m for flight to jet speed ratio 0.75. determine i) The flow of air through the propeller, ii) Thrust produced, iii) Specific thrust, iv) Specific impulse, v) Thrust power.

A turbo jet engine is traveling at a speed of 236.11 msec under conditions 288K and 1.013 bar. The ram efficiency is 85. Calculate the total pressure and total temperature of air after inlet diffuser. Take Cpa 1.005, Y1.4. For the above engine, the total temperature and total pressure at the inlet to the nozzle is 806k and 2.124 bar. The flow

A rocket flies at 10,080 kmph with an effective exhaust jet velocity of 1400 ms and propellant flow rate of 5.0 kgs. If the heat of reaction of the propellants is 6500 kJkg of the propellant mixture determine a) Propulsion efficiency and propulsion power, b) engine output and thermal efficiency, and c) overall efficiency.

Determine the maximum velocity of a rocket and the altitude attained from the following data Mass ratio Burn out time 0.15 75 s Effective jet velocity 2500 ms What are the values of the velocity and altitude losses due to gravity Ignore drag and assume vertical trajectory.

A missile has a maximum flight speed to jet speed ratio of 0.2105 and specific impulse equal to 203.88 seconds. Determine for a burn out time of 8 seconds. (a) effective jet velocity, (b) mass ratio and propellant mass fraction, (c) maximum flight speed, and (d) altitude gain during powered and coasting flights.

A rocket files at 10.080 kmph with an effective jet velocity of 1400 ms and the propellant flow rate of 5 kgs. if the heat of reaction of the propellants is 6500 kjkg of the propellent mixture, determine, a) Propulsion efficiency and propulsion power b) Engine output and thermal efficiency c) Overall efficiency

The following conditions refer to a rocker propellant flow rate 193 kgs. Thrust chamber pressure 27 bar and temperature 3000k. Nozzle exit diameter 600 mm. Nozzle exit pressure 1.1 bar and ambient pressure 1.013 bar. Thrust produced 380 kN. a) b) c) Find the effective jet velocity, actual jet velocity, specific impulse and the specific

A rocket has the following data Propellant flow rate 5 kgs Nozzle exit diameter 10 cm Nozzle exit pressure 1.02 bar Ambient pressure 1.013 bar Thrust chamber pressure 20 bar Thrust 7 KN Determine the effective jet velocity, actual jet velocity specific impulse and specific propellant consumption.

A rocket nozzle has a throat of 18cm and combustor pressure 25 bar. If the specific impulse is 127.42 and the rate of flow of propellant is 44.145 NS, determine the thrust coefficient, propellant weight flow coefficient specific propellant consumption and characteristic velocity.

A rocket engine has the following data Effective jet velocity 1400 ms Flight to jet speed ratio 0.82 Oxidizer flow rate 3.5 kgs Fuel flow rate 1.2 kgs Heat of reaction per kg of the exhaust gas 2600 KJkg. Calculate the thrust, specific impulse, propulsive efficiency, thermal efficiency and overall efficiency.

What are the different Welding Techniques.

In resistance welding, applied voltage V 5 v, spots per unit area, n25cm, spotbridge radius 0.01 cm, resistivity, p 2.0x105 ohmcm. Find Heat rate.

Two different pairs of sheets of the same material have to be resistance spot welded. One pair has 25 spotscm, average radius of spot is 0.1 mm. Other pair has 50 spotscm, average radius of spot is 0.1 mm. Find voltage ratio to get same heat generation

Consider a 5bottom 46cm semimounted mould board plough, pulled at 6.5kmh by a wheeled tractor. The average draft of plough is 30kN, when ploughing to a depth of 25cm. For an efficiency of 80 determine the i) 11) 111) iv) v) Specific draft (kNm) 52.22Nm2 Effective field capacity 1.196 Hah EFCa SWn 10 Actual drawbar power required. 54.2kW EFCm

Water is flowing at a rate of 0.25ms, and it is assumed that h1.5V2g from the reservoir to the gage, where V is the velocity in the 30cm pipe. What power must the pump supply

Water flow from a pressurized tank as shown. The pressure in the tank above the water surface is 100 kPa gage, and the water surface level is 10m above the outlet. The water exit velocity is 9ms. The head loss in the systerm varies as V 2g where KL is the headloss coefficient. Find the value for KL. h K

In the figure for Probs. 7.14 and 7.15, suppose that the reservoir is open to the atmosphere at the top. The valve is used to control the flow rate from the reservoir. The head loss across the valve is given as h 105 2g where V is the velocity in the pipe. The crosssectional area of the pipe is 5 cm. The head loss due to friction in the pipe is

A smallscale hydraulic power system is shown. The elevation difference between the reservoir water surface and the pond water surface downstream of the reservoir, H, is 10 m. The velocity of the water exhausting into the pond is 5 ms, and the discharge through the system is 1ms. The head loss due to friction in the penstock is negligible. Find the

Neglecting head losses, detedmine what power the pump must deliver to produce the flow as shown. Here the elevations at points A, B, C, and D are 40 m, 65 m, 35 m, and 30 m, respectively. The nozzle area is 30 cm.

As shown in the figure, the pump supplies energy to the flow such that the upstream pressure (12in. pipe) is 10 psi and the downstream pressure (6in. pipe) is 30 psi when the flow of water is 3.92 cfs. What horsepower is delivered by the pump to the flow Q pump in out

If a 200 N force F is applied to the piston with the 4 cm diameter, what is the magnitude of the force F2 that can be resisted by the piston with the 10 cm diameter Neglect the weights of the pistons. 4 cm diameter 2.2m 2 m 10 cm diameter Vertical Oil (SG0.85)

What is the pressure at the center of pipe B B 50 cm 10 cm. y10 kNm Y20 kNm 50 cm

Explain the Construction details and working working Clutches.

Discuss the Characterstics of following poiverplants CNG. Engure. LPG Engine. 1 . J

Air enters a compressor insulated against heat transfer at 37C and 105kPa pressure and exits at 610 kPa and 287C. Neglecting the change of kinetic and potential energy and also taking into account that specific heats change with temperature; a) Find the isentropic efficiency of the compressor, b) If the compression is reversible, find the outlet

Using the following data for chlorobenzene Specific volume0.904 Lkg Isothermal compressibility 7.45 x 105 bar Volume expansivity0.94 x 10 C1 I a. Compute the change in volume and work done when 1000 grams of chlorobenzene is heated from 288.15 K to 298.15 Kata constant pressure of 1 bar. b. Compute the final pressure when chlorobenzene is heated

Power required by an impellar in a mixing tank is a function of impellar diameter Da, speed of rotation N(rpm), density(p), viscosity () of the fluid besides accelration due to gravity. Using Bukingham theorem, get the dimensionless numbers involving power taking Da, N Dimensions of these varabiles in terms of fundamental units Property

A particle is moving along a straight line such that its acceleration is defined as an a kv. If Y Vowhen d 0 and t0, determine the particle Velocity as a function of position and the distance the particle moves before itstopes 3015

A particle has initial speed Vo, If it experiences a deceleration a bt de termine the distane travel before it 3

The 60 kg homogeneous smooth sphere rest on the 35 inclined plane A and bears against the smooth vertical wall B. The contact forces at A and B (in N) are respectively. (Take g 10 ms) in 35 A 60 kg (A) 732.46, 420.12 (B) 980.96, 532.4 (C) 790.89, 480.9 (D) 286.86, 146.4 B

(A) 80 N (C) 520 N (B) 150 N (D) 250 N,A smooth sphere weight 300 N is resting against smooth wall which is shown in figure below. The reaction at the support A is A D B 60

A short cylinder of circular cross section and weight Wis resting on a V block of angle 20. as shown in figure. The correct statement about reactions at point 4 and B isare MSQ W (A) Reaction at point A is (B) Reaction at point A is (C) Reaction at point B is (D) Reaction at point A is B W(2sin o.) W(2 cos a) W(2 sino) W(2 cos a)

000 For given truss, the force in member DF (in kN) is 3m 2m H 5m 2m 50 KN 2m 2m 50 kN 2m 5m 2m 2 m D 2m F 50 kN 3 m E

1 4 m 8 m For the given stadium roof truss, the magnitude of load in the member GI (in kN) will be 2m M 2 m 1 0.8 KN D 1.9 KN B 1.9 kN 0.95 KN 3m 3.5 m K 3.5m L

H wwwwwwwwww A truss hinged at A and supported on rollers at D is loaded as shown in figure. The magnitude of force in member BC is kN. 3 m F B 5 KN 3 m E 2 kN 3 m 450 4 m www D

For the given truss, the force in member 2 is 1000 N Aa (A) 250 N (C) ON 2 3 B 000 IAL 2.5 a (B) 500 N (D) 125 N

For a truss shown in the figure below, the force in member DE is,20 kN A B 3 m (A) 45 KN (C) 45 KN 70 kN C 3m (B) 10 KN (D) 25 KN D 3m 141 E 000

A case is placed around three parallel pipes as shown in figure. The coefficient of friction in each of three parallel pipes is 0.21, the value of smallest weight W for which equilibrium is maintained is kg. 40 kg A C W C B

A uniform ladder of weight 150 N rests against a smooth wall at the end 4 and at the end B, it rests on a rough horizontal floor with coefficient of friction 0.25. The angle of inclination (in degree) for the ladder, if it is on the verge of slipping is B 0 4 m,

A ladder 5 meter long rest on a horizontal ground and leans against a smooth vertical wall at an angle 70 with the horizontal. The weight of the ladder is 950 N and acts at its middle. The ladder is at the verge of sliding. When a man weighing 750 N stands on a rung 1.5 meter from the bottom of the ladder. The coefficient of friction between the