GATE Exam Preparation for Mechanical - Questions and Answers

1 Stokes theorem connects

Options

A) a line integral and a surface integral

B) a surface integral and a volume integral

C) a line integral and a volume integral

D) gradient of a function and its surface integral

Correct Answer A

2 Match the following

Type of Mechanism Motion achieved

P. Scott -- Russel mechanism 1. Intermittent motion

Q. Geneva mechanism 2. Quick return motion

R. Off-set slider-crank mechanism 3. Simple harmonic motion

S. Scotch Yoke mechanism 4. Straight line motion

Options

A) P-2 Q-3 R-l S-4

B) P-3 Q-2 R-4 S-l

C) P-4 Q-l R-2 S-3

D) P-4 Q-3 R-l S-2

Correct Answer C

3 A solar collector receiving solar radiation at the rate of 0.6 k W/m 2 transforms it to the internal energy of a fluid at an overall efficiency of 50%. The fluid heated to 350 K is used to run a heat engine which rejects heat at 313 K. If the heat engine is to deliver 2.5 kW power, the minimum area of the solar collector required would b

Options

A) 8.33m 2 B) 16.66m 2

C) 39.68m 2 D) 79.36m 2

Correct Answer D

4 When the temperature of a solid metal increases,

Options

A) strength of the metal decreaes but ductility increases

B) both strength and ductility of the metal decrease

C) both strength and ductility of the metal increase

D) strength of the metal increases but ductility decreases

Correct Answer A

5 A company produces two types of toys: P and Q. Production time of Q is twice that of P and the company has a maximum of 2000 time units per day. The supply of raw material is just sufficient to produce 1500 toys (of any type) per day. Toy type Q requires an electric switch which is available @ 600 pieces per day only. The company makes a profit of Rs. 3 and Rs. 5 on type P and Q respectively. For maximization of profits, the daily production quantities of P and Q toys should respectively be

Options

A) 100, 500 B) 500, 1000

C) 800, 600 D) 1000, 1000

Correct Answer C

6 A spherical thermocouple junction of diameter 0.706 mm is to be used for the measurement of temperature of a gas stream. The convective heat transfer co-efficient on the bead surface is 400 W/m 2 K. Thermophysical properties of thermocouple material are k = 20 W/mK, C = 400 J/kg K and r = 8500 kg/m 3 . If the thermocouple initially tot 30°C is placed in a hot stream of 300°C, the time taken by the bead to reach 298°C, is

Options

A) 2.35 s B) 4.9 s

C) 14.7 s D) 29.4 s

Correct Answer B

7 In a spring-mass system, the mass is 0.1 kg and the stiffness of the spring is 1 kN/m. By introducing a damper, the frequency of oscillation is found to be 90% of the original value. What is the damping coefficient of the damper?

Options

A) 1.2 N.s/m B) 3.4 N.s/m

C) 8.7 N.s/m D) 12.0 N.s/m

Correct Answer C

8 In a machining operation, doubling the cutting speed reduces the tool life to

18 of the original value. The exponent n in Taylor

Options

A)18

B)14

C)13

D)12

Correct Answer C

9 In a rolling process, sheet of 25 mm thickness is rolled to 20 mm thickness. Roll is of diameter 600 mm and it rotates at 100 rpm. The roll strip contact length will be

Options

A) 5 mm

B) 39 mm

C) 78mm

D) 120mm

10 The values of a function f(x) are tabulated below

x f(x)

0 1

1 2

2 1

3 10

Using Newton , s forward difference formula, the cubic polynomial that can be fitted to the above data, is

Options

A) 2x 3 + 7x 2 - 6x + 2

B)2x 3 - 7x 2 + 6x - 2

C)x 3 - 7x 2 - 6x2 + 1

D)2x 3 - 7x 2 + 6x + 1

11 Two tools P and Q have signatures 5°-5°-6°-6°-8°-30°-0 and 5°-5°-7°-7°-8°-15°-0 (both ASA) respectively. They are used to turn components under the same machining conditions. If hp and hQ denote the peak-to-valley heights of surfaces produced by the tools P and Q, the ratio hp/hQ will be

Options

A) B)

C) D)

12 A soldering operation was work-sampled over two days (16 hours) during which an employee soldered 108 joints. Actual working time was 90% of the total time and the performance rating was estimated to be 120 percent. If the contract provides allowance of 20 percent of the total time available, the standard time for the operation would be

Options

A) 8min. B) 8.9 min.

C) 10 min D) 12 min.

Correct Answer D

13 A welding operation is time-studied during which an operator was pace-rated as 120%. The operator took, on an average, 8 minutes for producing the weld-joint. If a total of 10% allowances are allowed for this operation, the expected standard production rate of the weld-joint (in units per 8 hour day) is

Options

A) 45 B) 50

C) 55 D) 60

Correct Answer A

14 In PERT analysis a critical activity has

Options

A) maximum Float B) zero Float

C) maximum Cost D) minimum Cost

Correct Answer B

15 Through holes of 10 mm diameter are to be drilled in a steel plate of 20 mm thickness. Drill spindle speed is 300 rpm, feed 0.2 mm/rev and drill point angle is 120°. Assuming drill overtravel of 2 mm, the time for producing a hole will be

Options

A) 4 Seconds B) 25 seconds

C) 100 seconds D) 110 seconds

16 Environment friendly refrigerant R134 a is used in the new generation domestic refrigerators. Its chemical formula is

Options

A) CH C1 F 2 B) C 2 C1 3 F 3

C) C 2 C1 2 F 4 D) C 2 H 2 F 4

Correct Answer D

17 A standard machine tool and an automatic machine tool are being compared for the production of a component. Following data refers to the two machines.

Standard Machine Tool

Automatic Machine Tool

Setup time 30 min. 2 hours

Machining time per piece 22 min. 5min

Machine rate Rs. 200 per hour Rs. 800 per hour

The breakeven production batch size above which the automatic machine tool will be economical to use, will be

Options

A) 4 B) 5

C) 24 D) 225

18 The mechanism of material removal in EDM process is

Options

A) Melting and Evaporation

B) Melting and Corrosion

C) Erosion and Cavitation

D) Cavitation and Evaporation

Correct Answer A

19 From a pack of regular playing cards, two cards are drawn at random. What is the probability that both cards will be Kings, if the first card is NOT replaced?

Options

A)126

B)152

C)1169

D)1221

Correct Answer D

20 The strength of a brazed joint

Options

A) decreases with increase in gap between the two joining surfaces

B) increases with increase in gap between the two joining surfaces

C) decreases up to certain gap between the two joining surfaces beyond which it increases

D) increases up to certain gap between the two joining surfaces beyond which it decreases

Correct Answer D