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# Indian Institute of Technology Kharagpur (IIT-K) 2007 B.Tech Mechanical Engineering Mid Semester - Question Paper

Wednesday, 23 January 2013 01:45Web

Mechanics
Mid Semesater exam -2007
IIT Kharagpur

INDIAN INSTITUTE OF TECHNOLOGY, KHARAGPUR

Date of Examination: 16.02.2007(FN)

Mid Semester Examination (Spring)

Time: 2hrs Full Marks:100 All First year

Subjcct No. ME10001 Subject Name: MECHANICS No. of students: iT50

Instructions: Answer all questions. All questions carry equal marks. Assume suitable data, if required.

All the members of the truss, shown in Fig. I have lm length, except EL. Determine force in the member EL.

2. Two links AC and CF are hinged together at C, as shown in Fig.2. The link CF is supported at E and the link AC is hinged at B with another link BD, supported at D. Determine the load P required to maintain equilibrium, if the load, W=10 kN.

Continued to reverse side

3. A transmission shaft, rotating at uniform speed, is driven by a belt drive as shown in Fig.3. The pulley E has a radius of 200 mm and the gears A and C both have radius of 100mm. Determine (a) T| and (b) the equivalent force system at bearing B, for all the forces shown in the figure. Assume that the bearings are incapable of resisting any moment as well as axial force.

An indusrial truck is required to push a paper roll of 12 kN up the incline, as shown in Fig.4. Compute the tractive force required by the truck.

5a) A braking device for a rotating machine shaft is shown in Fig.5a. By applying force F, which is acting perpendicular to the lever, the belt grip over the pulley can be increased to reduce the speed. While reducing the-speed of the pulley by above stated manner, at one point of time, it is observed that the speed of rotation is 1200 rpm and corresponding power transmission is 5 kW. Determine the magnitude of the force F for this condition.

 FIG-4

Co-efficient of friction between the belt and the pulley =0.3 Mean diameter of the screw = 30 mm Pitch of the screw = 6 mm (single thread)

Co-efficient of screw friction = 0.15

5b) A friction device, for power transmission in perpendicular direction, is shown in Fig.5b. A torque Ts is applied to the smaller disc, S, of radius r and weight W. To maintain equilibrium, determine, with a neat free body diagram, the torque Tl transmitted to the larger disc, L, of radius R. The contact between the discs are at the rim of the bigger disc.