STUPIDSID
1(a)
Distinguish between mechanism and machine.
2 M
1(b)
Write and explain Gruebler's Kutzbach criterion.
2 M
1(c)
universal joint if the driving shaft rotates at 800 rpm and the total fluctuation of speed does not exceed 60 rpm. Also find the maximum and minimum speeds of the driven shaft.
3 M
Solve any one question from Q.1(d) & Q.1(e)
1(d)
Determine the maximum permissible angle between the shaft axes of a univarsal joint if the driving shaft rotates at 800 rpm and the total fluctuation of speed does not exceed 60 rpm. Also find the maximum and minimum speeds of the driven shaft.
7 M
1(e)
The length of the fixed link of a crank and slotted-lever mechanism is 250 mm and that of the crank is 100mm. Determine the inclination of the slotted lever with the vertical in the extreme position, ratio of the time of cutting stroke to the time of return stroke, and the length of stroke, if the length of the slotted lever is 450 mm and the line of stroke passes through the extreme positions of the free end of the lever.
7 M
2(a)
State and explain the Kennedy's Theorem.
2 M
2(b)
Explain the Rubbing velocity at a pin joint.
2 M
2(c)
What is a velocity image? State why it is known as a helpful device in the velocity analysis of complicated linkage.
3 M
Solve any one question from Q.2(d) & Q.2(e)
2(d)
What do you mean by coriolis component of acceleration? When will it exist? Prove that this component of acceleration is equal to:2×Vω
Where: ω- Angular velocity of the rotating link.
V-Linear velocity of the slider along the link.
Where: ω- Angular velocity of the rotating link.
V-Linear velocity of the slider along the link.
7 M
2(e)
A link AB of a four bar mechanism ABCD revolves uniformly at 120 rpm in a clockwise direction. Find the angular acceleration of links BC, CD and point E (lie in the link BC). Given: AB=7.5 cm, BC=17.5 cm, EC=5 cm, CD=15cm, DA=10 cm and ∠BAD=90*deg;
7 M
3(a)
State the law of Gearing.
2 M
3(b)
What do you mean by pitch point, module, addendum and dedendum of a gear?
2 M
3(c)
Explain what is interference and how it is prevented.
3 M
Solve any one question from Q.3(d) & Q.3(e)
3(d)
Two 20° involute spur gear mesh externally and give a velocity ratio of 3. The module is 3mm and the addendum is equal to 1.1 module. If the pinion rotates at 120 rpm, determine contact ratio and the minimum number of teeth on each wheel to avoid interference.
7 M
3(e)
Two left-handed helical gears connect two shafts 60° apart. The normal module is 6 mm. The larger gear has 70 teeth and the velocity ratio is ½ . The center distance is 370mm. Find the helix angles of the two gears.
7 M
4(a)
List the different motions that a follower can have.
2 M
4(b)
Explain pitch circle, prime circle and base circle.
2 M
4(c)
Draw the displacement, velocity and acceleration diagrams for a follower when it moves with simple harmonic motion.
3 M
Solve any one question from Q.4(d) & Q.4(e)
4(d)
Draw the profile of a cam operating a roller reciprocating follower and with the following data:
i) Minimum radius of cam is 25mm
ii) Lift of follower is 30mm
iii) Roller diameter is 15mm.
The cam lifted the follower for 120° with simple harmonic motion followed by a dwell period of 30°. Then the followers lower during 150° of the cam rotation with uniform acceleration and deceleration followed by a dwell period. If the cam rotates at a uniform speed of 150rpm, determine the maximum velocity and acceleration of the follower during the decent period.
i) Minimum radius of cam is 25mm
ii) Lift of follower is 30mm
iii) Roller diameter is 15mm.
The cam lifted the follower for 120° with simple harmonic motion followed by a dwell period of 30°. Then the followers lower during 150° of the cam rotation with uniform acceleration and deceleration followed by a dwell period. If the cam rotates at a uniform speed of 150rpm, determine the maximum velocity and acceleration of the follower during the decent period.
7 M
4(e)
Draw the profile of a cam operating a knife-edge follower from the following data:
i) Follower to move outward through a distance of 20mm during 120° cam rotation.
ii) Follower to dwell for the next 60& of cam rotation.
iii) Follower to return to its initial position during 90°
iv)Follower to dwell for the remaining 90°: of cam rotation. The cam rotating clockwise at a uniform speed of 500 rpm. The maximum radius of the cam is 40 mm and the line of stroke of eh follower of offset 15mm from the axis of the cam and the displacement of the follower is to take place with uniform and equal acceleration and retardation on both the outward and the return strokes. Determine the maximum velocity and acceleration of the follower during outward and return strokes.
i) Follower to move outward through a distance of 20mm during 120° cam rotation.
ii) Follower to dwell for the next 60& of cam rotation.
iii) Follower to return to its initial position during 90°
iv)Follower to dwell for the remaining 90°: of cam rotation. The cam rotating clockwise at a uniform speed of 500 rpm. The maximum radius of the cam is 40 mm and the line of stroke of eh follower of offset 15mm from the axis of the cam and the displacement of the follower is to take place with uniform and equal acceleration and retardation on both the outward and the return strokes. Determine the maximum velocity and acceleration of the follower during outward and return strokes.
7 M
5(a)
Explain the Gyroscopic couple.
2 M
5(b)
Explain the terms spin and p recession.
2 M
5(c)
Drive and expression for Gyroscopic torque in terms of angular velocity of spin, angular velocity of p recession and polar mass moment of inertia of a disc.
3 M
Solve any one question from Q.5(d) & Q.5(e)
5(d)
An air craft consists of a propeller. It also consists of engine and propeller at 3600 rpm in a sense clockwise looking from rear. The air craft completes half circle of radius 100 m towards left when flying at 360 km/hr. Determine the gyroscopic couple on the air-craft.
7 M
5(e)
A four wheel car weighs 30kN. Each axle with its two wheels and gears has a total mass moment of inertia of 35kg-m2. Each wheel is 500mm radius. The cent re distance between two wheels on an axie is 1.4m. Each motor along with its gear has a mass moment of inertia of 15kg-m2 and rotates in the opposite direction to that axle. The cent re of gravity of the car is located at 1m above the rails. Determine the limited speed of the car while negotiating a curve of 200m radius without the wheels leaving the rails.
7 M
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