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DR. BABASAHEB AMBEDKAR TECHNOLOGICAL UNIVERSITY,
Summer Semester Examination May 2019
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Semester: IV
Branch: B.Tech. (Mechanical)
Subject with Subject Code: Theory of Machines-I (BTMEC402) Marks: 60
Date: 16/05/2019 Time:3 Hrs.
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Instructions to the Students
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. Each question carries 12 marks.
. Attempt any five questions of the following.
. If some part or parameter is noticed to be missing, you may appropriately assume it and should mention it clearly.
. Non programmable calculator is allowed.
. Graphical numerical should solve on only drawing sheet.
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(Marks)
Q.1.
A. Explain in detail with diagram. Types of constrained motions.
(05)
B. Locate all the instantaneous centres of the slider crank mechanism as shown in Fig.. The lengths of crank
OB and connecting rod AB are 100 mm and 400 mm respectively. If the crank rotates clockwise with an
angular velocity of 10 rad/s, find: 1. Velocity of the slider A, and 2. Angular velocity of the connecting rod
AB (Graphical Method).
(07)
Q.2.
A. The dimensions and configuration of the four bar mechanism, shown in Fig., are as follows : P1A = 300
mm; P2B = 360 mm; AB = 360mm, and P1P2 = 600 mm. The angle AP1P2 = 60°. The crank P1A has an
angular velocity of 10 rad/s and an angular acceleration of 30 rad/s2, both clockwise. Determine the angular
velocities and angular accelerations of P2B, and AB and the velocity and acceleration of the joint B.
(Graphical Method)
(
07)
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B. The crank and connecting rod of a reciprocating engine are 200 mm and 700 mm respectively. The crank
is rotating in clockwise direction at 120 rad/s. Find with the help of Klein’s construction: 1. Velocity and
acceleration of the piston, 2. Velocity and acceleration of the mid point of the connecting rod, and 3. Angular
velocity and angular acceleration of the connecting rod, at the instant when the crank is at 30° to I.D.C. (inner
(05)
Q.3.
A. conical pivot supports a load of 20 kN, the cone angle is 120º and the intensity of normal pressure is not
to exceed 0.3 N/mm2. The external diameter is twice the internal diameter. Find the outer and inner radii of
the bearing surface. If the shaft rotates at 200 r.p.m. and the coefficient of friction is 0.1, find the power
absorbed in friction. Assume uniform pressure.
(07)
B. State the laws of
(i) Static friction ; (ii) Dynamic friction
(05)
Q.4.
A. Determine the maximum, minimum and average pressure in plate clutch when the axial force is 4 kN. The
inside radius of the contact surface is 50 mm and the outside radius is 100 mm. Assume uniform wear. (06)
B. A single block brake is shown in Fig. The diameter of the drum is 250 mm and the angle of contact is90°.
If the operating force of 700 N is applied at the end of a lever and the coefficient of friction between the drum
and the lining is 0.35, determine the torque that may be transmitted by the block brake.
(06)
Q.5.
A. Explain with sketches the different types of followers.
(08)
B. Define the following terms
(04)
i. Trace point
ii. Pressure angle
iii. Pitch curve
iv. Prime circle
Q.6.
A. Explain balancing of several masses rotating in same plane by analytical method.
(06)
B. Four masses m1, m2, m3 and m4 are 200 kg, 300 kg, 240 kg and 260 kg respectively The corresponding
radii of rotation are 0.2 m, 0.15 m, 0.25 m and 0.3 m respectively and the angles between successive masses
are 45°, 75° and 135°. Find the position and magnitude of the balance mass required, if its radius of rotation
is 0.2 m (Analytically).
(06)
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