engineering mechanic (old)

7/28/2019 Engineering Mechanic (Old)

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Code No. : 3007/0FACULTY OF ENGINEERING /INFORMATICS

B.E. I Year (Common to all Branches) (Old) Examination, June 2011ENGINEERING MECHANICSTime: 3 Hours"] [ Max. Marks: 75

questions of Part - A. Answer five questions from

1.

2. If the resultantof two forcesP andQ actingat anangleewith P thenPsin e P cos e(a) tan e = P Q e (b) tan e = P Q ecos + cosQ sin e Q cose(c) tan e = P Q e (d) tan e = P Q ecos + cos

2

3. The Lami's theorem is applicable for(a) Coplanar forces(c) Coplanar concurrent forces (b) Concurrent forces(d) " Any typeof forces

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4. For a perfect frame having 13 members the number of joints must beW 6 ~ 8(c) 10 (d) 13

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5. The C.G. of a semicircle lies at a distance of from its basemeasured along the vertical radius. 2(a) 3R (b) 4R4n 3n(c) 4n (d) 83R 3R


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7.

8.

9.

Code No. : 300710

A body of weight 100 N moved up on a horizontal plane having f..l=~ .The maximum force applied at an angle to the horizontal to move the bodyup is 3(a) 10~ N (b) 50 N(c) 100 N (d) 100\[2A particle with ini.tialvelocity of 2m/sec moving with a uniform retardation of0.1 m/sec2 has travelled 15 m. Find out the time taken by the particle totravel the distance of 15 m. 3A train is moving along a track whose gradient is 1 in 100. The weight ofthe train is 5 MN. To avoid an accident the train is brought to rest applyingbrakes in 200 m length along the track. Resistance due to friction and airmotion is 10 N/kN weight of the train. Find the work done in bringing thetrain to rest. 3

10. The amplitude of a SHM is 2 m and the period is one second. Determinethe maximum velocity,and the maximum acceleration. 3

11. (a)

12. (a)(b)

13. (a)

(b)

PART - B (Marks: 50)Reduce the following set of forces to a single resultant force acting atthe origin of the coordinate axis and a couple 5F = 140 N acting from A (3, 7, -1) towards 8(5,1,2).P = 260 N acting from C(-6, 4, 1) towards D(6, 7, 5).T = 270 N acting from E(;-2, 4, 1) towards G(4, -2, 4).A roller of 60 cms diameter and 2500 N weight is to be pulled over anobstacle height of 15 cm by a horizontal pull F applied at the top endpoint of the wheel. Find the minimum magnitude of F required tooverturn the wheel over the obstacle. 5

State and prove Pappus theorems. . 5Locate the CG of a symmetrioal trapezium with parallel sides ofdimensions 'a' and 'b' and height 'h'. 5Determine the force required to state the wedge as shown in the fig.


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14. (a)

15. (a)(b)

16. (a)

Code No.: 3007/0

(b)

A stone is projected vertically up with a velocity of 25 m/sec. Find(i) when it willbe 40 m above the point of projection(ii) the time of flight.(iii) the velocity of stone 2 sec after projection.The armature of an electric motor was rotating at 1500 rpm at aninstant, when power was cut off. Find out the angular retardation ifthe shaft stops rotating within5 sec. Find out the number of rotations/made by the shaft. 4

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State the principle of virtualwork. 4Find the breaking torque produced by a force 40 N applied to thelever of the band break at point 0 as shown in Fig. The coefficient offrictionbetween flywheeland belt is 0.4. . 6

15cm 60cm 40N

Flywheel of radius 15 cmhinged at centre.

(b)

A train of weight 2000 kN running at 60 km/hr. experiences totalresistances of 10 N/kNwt. of the train. Determine the power requiredwhen 5(i) the train is moving along a level track.(ii) the train is moving up an inclined plane of gradient one inhundred.A bullet of mass 120 gms is fired into a target with a velocity of400 m/sec. If the mass of a target is 10 kg and it is free to move, findthe loss in kinetic energy. 5

17. A particle follows SHM and its velocities at a distance of 1 m and 2 m fromcentre are 4 m/sec and 2 m/sec respectively. Find' 10(a) the amplitude and periodic time.(b) find the acceleration when thedisplacements1.5m.

engineering mechanic (old)

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