Mechanical Engineering Set 1

Mechanical Engineering

1 What state the first law of Thermodynamics?

Conservation of Energy

Conservation of Momentum

Conservation of Mass

Conservation of Charge

2 At any point on the saturation curve in psychometric chart, the dry bulb temperature is always

Equal to the corresponding wet bulb temperature

More than the corresponding wet bulb temperature

Less than the corresponding wet bulb temperature

Cannot predict

3 For the same capacity of plant, the COP of the vapour absorption refrigeration system is

Lower than the COP of the vapour compression refrigeration system

Higher than the COP of the vapour compression refrigeration system

Same as the COP of the vapour compression refrigeration system

cannot say

4 For a same pressure the saturation temperature of ammonia is

Lower than the saturation temperature of water

Higher than the saturation temperature of water

Same as the saturation temperature of water

None of these

5 What is an advantage using analyser-rectifier in aqua-ammonia absorption system?

It prevents expansion valve from blocking due to ice formation

It makes ammonia-water solution strong

It prevents expansion valve from blocking due to ice formation

Both it prevents expansion valve from blocking due to ice formation and it makes ammonia-water solution strong

6 Which among the following engines is NOT the type of aircraft gas turbine which works on jet propulsion cycle?

None of these

Turboprop

Turbofan

Turbojet

7 The maximum limit of the pressure ratio of the Brayton cycle for maximum efficiency

Is equal to the pressure ratio of the Carnot cycle

Is more than the pressure ratio of the Carnot cycle

Is less than the pressure ratio of the Carnot cycle

Can not say

8 The feed water heater in which the extracted steam and feed water have thermal contact for exchanging heat but the extracted steam is not allowed to mix with the feed water is called as

Closed type feed water heater

Contact type feed water heater

Open type feed water heater

None of these

9 When the thermodynamic criterion of equilibrium (H, S, U, G or F) remains constant for all possible variation of finite magnitude then the system is said to be in

Neutral equilibrium

Meta-stable equilibrium

Unstable equilibrium

None of these

10 What is the dryness fraction (x) for saturated water, when water just starts boiling?

x = 0

x = 1

x = 0.9

x = 0.5

11 If m1 and m2 are the masses of liquid and vapour respectively in a liquid-vapour mixture, then what is the formula for dryness fraction x?

x = m2 / (m1 + m2)

x = m1 / (m1 + m2)

x = (m1 + m2) / m2

x = (m1 + m2) / m1

12 Arbitrarily, the value of triple point is taken as

273.16 K

273.16 Degree C

0 K

None of These

13 The ratio of effective length and least lateral dimension for short column is _______

< 12

> 12

≥ 12

None of these

14 In Euler’s theory, long columns having the ratio of (Le /LLD) ≥ 12 fail due to _______

Buckling

Both buckling and crushing

Crushing

All of these

15 Euler’s formula is applicable only _________ 1. for short columns 2. for long columns 3. if slenderness ratio is greater than √(π2 E / σc) 4. if crushing stress < buckling stress 5. if crushing stress ≥ buckling stress

2, 3 and 5

1, 2 and 3

3 and 4

All of these

16 What is the relation between actual length and effective length while determining crippling load for a hollow rectangular cast iron column having both ends fixed? (where L= actual length and Le =effective length)

Le = L/2

Le = 4L

Le = 2L

Le = L

17 When a component is subjected to axial stress the normal stress σn is maximum, if cos θ is _______ . (σn=σxCos2θ) 1. maximum 2. minimum 3. always one 4. always zero

1 and 3

1 and 4

2 and 3

2 and 4

18 Virtual number of teeth on pinion of bevel gear is calculated using the formula __________ (where zp = number of teeth on pinion, γp & γg = pitch cone angle)

zp / cos γp

zp / cos γg

zp / cos2 γp

zp / cos3 γp

19 What is the axial force acting on the pinion if a bevel gear transmits power of 20 kW with a mean pitch line velocity of 5 m/s? (Consider γp = 25o & Φ = 15o)

452.96 N

971.37 N

1801.67 N

1865 N

20 At zero acceleration a particle moves along a straight line. What is the velocity of a particle at the position of x = t4 -20t2 + 42 ?

+ 48.68 m/sec

– 48.68 m/sec

+ 42 m/sec

– 42 m/sec

 

21 What is the initial velocity of an object which travels a distance of 10t2 +15t + 5 along a straight line in time t?

+15

-15

+10

-10

 

22 Two cars X and Y move on adjacent roads in opposite directions. If velocity of car X and Y is 80 km/hr and 60 km/hr respectively, then what will be the relative velocity of car X w.r.t. Y?

140 km/hr

100 km/hr

70 km/hr

Insufficient data

 

23 What is the maximum distance traveled by a block moving upwards on an inclined plane of 30o with velocity of 20 m/s, if coefficient of friction is 0.23 between the block and inclined plane?

29.19 m

22.56 m

17.32 m

17.00 m

 

24 What is the path equation for a particle having x = 6t and y = 4t^2 ?

x^2 = 6y

x^2 = 9y

y^2 = 8x

y = 9x

 

 

25 A particle moves along a path y = x2 – 6x + 200. If vx = 6 m/s , what is the value of vy at x = 30?

324 m/s

300 m/s

354 m/s

None of these

 

26 A car moves along a circular arc at a speed of 30 m/s, if speed of the car is increased at the rate of 50 m/s^2, what is the resultant acceleration of the car? (Radius of arc = 15 m)

78.10 m/s^2

33.16 m/s^2

60.23 m/s^2

58.10 m/s^2

 

27 Which of the following factors are related by work energy principle?

Force, velocity, displacement

Force, velocity, time and mass

Force, displacement and time

Displacement, time and mass

 

28 If coefficient of restitution is zero during plastic impact, then ___________

Momentum energy is conserved

Kinetic energy is conserved

Bodies move away after impact

All of these

 

29 Coefficient of restitution is the ratio of impulse during __________

Restoration period and deformation period

Deformation period and restoration period

Plastic deformation and elastic deformation

Elastic deformation and plastic deformation

 

30 Which of the following conditions is satisfied for cantilever truss?

n = 2j – R

n ≠ 2j – R

n < 2j – R

n > 2j – R

 

31 What is the relation between tight side and slack side for a flat belt?

(Tight side / slack side) = eμβ

(Tight side + slack side) = eμβ

(Tight side x slack side) = eμβ

None of these

 

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