Ministry of Higher Education Class :- 3rd
& Scientific Research Subject :- Theory of machain
Tikrit University hrs..Time 3
Form ( 3 )
Second Attempt
College of engineering Final Exam Date / 9 / 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 – The mechanism shown is drawn to a scale of 1mm = 1 mm. If the angular velocity of link 2 = 50 rad/s
,in the CCW sense
a) Draw the velocity polygon and determine the velocity of point G5
Q.3 – Answer two
branches of the
following
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) – Describe with a neat sketch a centrifugal clutch and deduced an equation for the total torque
transmitted.
(C) - How the different masses rotating in different planes are balanced ?
Q.4 – Two shafts A and B are co-axial. A gear C (50 teeth) is rigidly mounted on shaft A. A compound gear
D-E gears with C and an internal gear G. D has 20 teeth and gears with C and E has 35 teeth and gears with
an internal gear G. The gear G is fixed and is concentric with the shaft axis. The compound gear D-E is
Ministry of Higher Education Class :- 3rd
& Scientific Research Subject :- Theory of machain
Tikrit University hrs..Time 3
Form ( 3 )
Second Attempt
College of engineering Final Exam Date / 9 / 2017
.Mechanical Eng. Dept 2016-
2017
mounted on a pin which projects from an arm keyed to the shaft B. find the number of teeth on internal gear
G assuming that all gears have the same module. If the shaft A rotates at 110 r.p.m., find the speed of shaft
B.
Q.5 – A cam, with a minimum
radius of 25 mm, rotating
clockwise at a uniform speed is to be designed to give a roller follower, at the end of a valve rod, motion
described below :
1. To raise the valve through 50 mm during 120° rotation of the cam ;
2. To keep the valve fully raised through next 30°;
3. To lower the valve during next 60°; and
4. To keep the valve closed during rest of the revolution i.e. 150° ;
The diameter of the roller is 20 mm and the diameter of the cam shaft is 25 mm.
A- Draw the profile of the cam when
(i) the line of stroke of the valve rod passes through the
axis of the cam shaft, and
(ii) the line of the stroke is offset 15 mm from the axis of the cam shaft.
B- Draw the displacement, the velocity and the acceleration diagrams for one complete revolution
of the cam
C- Determine the maximum acceleration of the valve rod when the cam shaft rotates
at 100 r.p.m.
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 ( 3 )
Second Attempt
College of engineering Final Exam Date / 9 / 2017
.Mechanical Eng. Dept 2016-
2017
Ministry of Higher Education Class :- 3rd
& Scientific Research Subject :- Theory of machain
Tikrit University hrs..Time 3
Form ( 3 )
Second Attempt
College of engineering Final Exam Date / 9 / 2017
.Mechanical Eng. Dept 2016-
2017
Ministry of Higher Education Class :- 3rd
& Scientific Research Subject :- Theory of machain
Tikrit University hrs..Time 3
Form ( 3 )
Second Attempt
College of engineering Final Exam Date / 9 / 2017
.Mechanical Eng. Dept 2016-
2017
Ministry of Higher Education Class :- 3rd
& Scientific Research Subject :- Theory of machain
Tikrit University hrs..Time 3
Form ( 3 )
Second Attempt
College of engineering Final Exam Date / 9 / 2017
.Mechanical Eng. Dept 2016-
2017
Ministry of Higher Education Class :- 3rd
& Scientific Research Subject :- Theory of machain
Tikrit University hrs..Time 3
Form ( 3 )
Second Attempt
College of engineering Final Exam Date / 9 / 2017
.Mechanical Eng. Dept 2016-
2017
Ministry of Higher Education Class :- 3rd
& Scientific Research Subject :- Theory of machain
Tikrit University hrs..Time 3
Form ( 3 )
Second Attempt
College of engineering Final Exam Date / 9 / 2017
.Mechanical Eng. Dept 2016-
2017
Ministry of Higher Education Class :- 3rd
& Scientific Research Subject :- Theory of machain
Tikrit University hrs..Time 3
Form ( 3 )
Second Attempt
College of engineering Final Exam Date / 9 / 2017
.Mechanical Eng. Dept 2016-
2017
Ministry of Higher Education Class :- 3rd
& Scientific Research Subject :- Theory of machain
Tikrit University hrs..Time 3
Form ( 3 )
Second Attempt
College of engineering Final Exam Date / 9 / 2017
.Mechanical Eng. Dept 2016-
2017
Good Luck
.................. :Examier
Ministry of Higher Education Class :- 3rd
& Scientific Research Subject :- Theory of machain
Tikrit University hrs..Time 3
Form ( 3 )
Second Attempt
College of engineering Final Exam Date / 9 / 2017
.Mechanical Eng. Dept 2016-
2017
