Ministry of Higher Education Class :- 3rd
& Scientific Research Subject :- Theory of machain
Tikrit University hrs..Time 3
Form ( 1 )
First Attempt
College of engineering Final Exam Date 7 / 6 / 2017
.Mechanical Eng. Dept 2016-
2017
الدرجات موزعة بالتساوي على- تسلم ورقة األسئلة مع دفتر االمتحان: مالحظة
االجابة على جميع االسئلة- .االسئلة
Q.1- For the mechanisms shown in figures below
i) Describe the motion of each links and identify the pairings .
.ii) Determine the mobility of mechanism
Q.2 – Crank O2A of a drag-link mechanism rotates at a constant angular velocity of 50 rad/s in the clockwise
.sense. The mechanism is drawn with a scale of 1mm = 5mm
;Draw the velocity polygon to a scale of 1mm = 0.05 /s and determine )a(
i) The velocity of sliders 4 and 6
. ii) The angular velocity of links 3 and 5
Q.3 – In an epicyclic gear train, the internal wheels A and B and compound wheels C and D rotate
independently about axis O. The wheels E and F rotate on pins fixed to the arm G. E gears with A and C and
F gears with B and D. All the wheels have the same module and the number of teeth are : TC = 28; TD = 26;
TE = TF = 18.
1. Find the number of teeth on A and B ;
2. If the arm G makes 100 r.p.m. clockwise and A is fixed, find the speed of B .
Ministry of Higher Education Class :- 3rd
& Scientific Research Subject :- Theory of machain
Tikrit University hrs..Time 3
Form ( 1 )
First Attempt
College of engineering Final Exam Date 7 / 6 / 2017
.Mechanical Eng. Dept 2016-
2017
If the arm G makes 100 r.p.m. clockwise and wheel A makes 10 r.p.m. counter clockwise ; find the speed .3
of wheel B
Q.4 – A cam with a minimum radius of 50 mm, rotating clockwise is to be designed to give a knife edge
follower at the end of a valve rod, motion to raise the valve through 40 mm in 16.7% of a revolution the
follower moves with uniform velocity and keep it fully raised through 8.33% revolution and to lower it with
uniform motion in 16.7% revolution. The valve remains closed during the rest of the revolution. The axis of
the valve rod passes through the axis of the camshaft. If the camshaft rotates at of 100 r.p.m.
i- Draw the cam profile.
ii- find the maximum velocity and acceleration of a valve during raising and lowering.
Q.5 – Answer one branch of thefollowing questions.
(A) – Four masses m1, m2, m3 and m4 are 175 kg, 202 kg, 230 kg and 270 kg respectively .The
corresponding radii of rotation are 0.22 m, 0.155 m, 0.255 m and 0.33 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.
(B) – If the capacity of a single plate clutch decreases by 20 % during the initial wear period, determine the
minimum value of the ratio of internal diameter to external diameter for the same axial load. Consider both
the sides of the clutch plate to be effective.
Good luck
Examiner
.Head of the Dept
Assistant prof. Adel M. Al-Bash
Dr. Hameed Jassem
Ministry of Higher Education Class :- 3rd
& Scientific Research Subject :- Theory of machain
Tikrit University hrs..Time 3
Form ( 1 )
First Attempt
College of engineering Final Exam Date 7 / 6 / 2017
.Mechanical Eng. Dept 2016-
2017
Ministry of Higher Education Class :- 3rd
& Scientific Research Subject :- Theory of machain
Tikrit University hrs..Time 3
Form ( 1 )
First Attempt
College of engineering Final Exam Date 7 / 6 / 2017
.Mechanical Eng. Dept 2016-
2017
Good
Luck
Ministry of Higher Education Class :- 3rd
& Scientific Research Subject :- Theory of machain
Tikrit University hrs..Time 3
Form ( 1 )
First Attempt
College of engineering Final Exam Date 7 / 6 / 2017
.Mechanical Eng. Dept 2016-
2017
.................. :Examier
Head of Dept. Dr. Hameed J. Khalaf
