Mechanical Engineering Gate 2025 Questions with Answer

Ques 27 GATE 2025


Water enters a tube of diameter, D = 60 mm with mass flow rate of 0.01 kg s-1 as shown in the figure below. The inlet mean temperature is Tm,i=293 K and the uniform heat flux at the surface of the tube is 2000 W m-2. For the exit mean temperature of Tm,o=353 K, the length of the tube, L is ______ m (rounded off to 1 decimal place).
Use the specific heat of water as 4181 Jkg-1 K-1.


(1.9) is the correct answer.

Ques 28 GATE 2025


Considering the actual demand and the forecast for a product given in the table below, the mean forecast error and the mean absolute deviation, respectively, are

Period12345678910
Actual demand425421426416422418430420415427
Forecast427418423422416422415430419420

A

0.8 and 42.0

B

0.8 and 4.2

C

8.0 and 42.0

D

8.0 and 4.2


(b) is the correct answer.

Ques 29 GATE 2025


A company uses 3000 units of a part annually. The units are priced as given in the table below. It costs ¥150 to place an order. Carrying costs are 40 percent of the purchase price per unit on an annual basis. The minimum total annual cost is ______ (rounded off to 1 decimal place).

Order quantityUnit price (¥)
1 to 4999.0
500 to 9998.5
1000 or more8.0


(10800.0) is the correct answer.

Ques 30 GATE 2025


A project involves eight activities with the precedence relationship and duration as shown in the table below. The slack for the activity D is ______ hours (answer in integer).

ActivityImmediate predecessorDuration (hours)
A4
BA8
CA5
DB2
EB7
FC6
GD3
HE, F, G9


(4) is the correct answer.

Ques 31 GATE 2025


When assembled, the hole 30+0.030+0.020 mm and shaft 30-0.020-0.030 mm will result in

A

loose fit

B

interference fit

C

transition fit

D

clearance fit


(d) is the correct answer.

Ques 32 GATE 2025


A shaft carries a helical spur gear. Which one of the following bearings can NOT be used to support it?

A

Angular contact bearing

B

Double-row ball bearing

C

Straight roller bearing

D

Tapered roller bearing


(c) is the correct answer.

Ques 33 GATE 2025


The endurance limit of a specific grade of steel is same as its yield strength. The ultimate strength of this grade of steel is twice of its yield strength. A component made of this steel is loaded in tension and unloaded periodically. It is required that the component does NOT fail for at least 106 loading cycles, as per the Soderberg law. Considering a factor of safety of 2, the maximum applied tensile principal stress is

A

one-fourth of the endurance limit

B

half of the endurance limit

C

the endurance limit

D

twice the endurance limit


(b) is the correct answer.

Ques 34 GATE 2025


A pair of spur gears is required to maintain a velocity ratio of 1:2. The module of the gears is 10 mm and the addendum is 10 mm. If the operating pressure angle is 15° the minimum number of teeth required on the pinion to ensure NO interference/undercutting is ______ (answer in integer).


(18) is the correct answer.

Ques 35 GATE 2025


Two plates of thickness 10 mm each are to be joined by a transverse fillet weld on one side and the resulting structure is loaded as shown in the figure below.
If the ultimate tensile strength of the weld material is 150 MPa and the factor of safety to be used is 3, the minimum length of the weld required to ensure that the weld does NOT fail is ______ mm (rounded off to 2 decimal places).


(28.28) is the correct answer.

Ques 36 GATE 2025


Among the following surface hardening processes, steel is heated to the lowest temperature in

A

carburizing

B

cyaniding

C

nitriding

D

carbonitriding


(c) is the correct answer.

Ques 37 GATE 2025


The welding process commonly used for fabricating tailor-welded blanks of dissimilar thickness for automotive applications is

A

gas welding

B

laser welding

C

arc welding

D

friction welding


(b) is the correct answer.

Ques 38 GATE 2025


In computer aided design (CAD), solid models can be constructed using

A

boundary representation (B-rep)

B

Bezier curves

C

B-splines

D

nonuniform rational B-splines (NURBS)


(a) is the correct answer.

Ques 39 GATE 2025


Ceramics and glass are machined by

A

electric discharge machining

B

ultrasonic machining

C

electrochemical machining

D

transferred arc plasma machining


(b) is the correct answer.

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