JNTU
JNTU B.Tech III Year DYNAMICS OF MACHINERY Previous Question Paper (September - 2021 - R16)
Answer any five questions. All questions carry equal marks.
Main
What is the effect of gyroscopic on naval ships?
Answer
The gyroscopic effect on a naval ship is observed during steering, pitching, and rolling. When a ship steers, the gyroscopic couple acts in a plane perpendicular to the axis of spin and the axis of steering, causing the bow to rise or fall depending on the direction of the turn and the rotation of the rotor. During pitching, the gyroscopic couple acts in a plane perpendicular to the axis of spin and the axis of pitching, which creates a reactive couple that tends to turn the ship about the longitudinal axis, causing it to roll. During rolling, the axis of spin remains parallel to the longitudinal axis, and since there is no change in the angular momentum vector direction, no gyroscopic couple is exerted.
What is the effect of centrifugal couple on the stability of an automobile?
Answer
The centrifugal couple acts on an automobile when it takes a turn, primarily due to the lateral force acting at the center of gravity. This force creates a tendency for the vehicle to overturn about the outer wheels. The magnitude of this overturning couple is given by
A four link mechanism, is acted upon by a 80 N and 150 N force on the link DC. AD=500, AB=400, BC=1000, DC=750, DE=350. Determine the input torque T on the link AB using analytic method for the static equilibrium of the mechanism for the given configuration.
Answer
Sign in to view the complete answer paper.
Derive the expression for turning moment required on the crankshaft.
Answer
Sign in to view the complete answer paper.
Explain the determination of inertia forces in reciprocating engines using graphical networks.
Answer
Sign in to view the complete answer paper.
An otto cycle engine develops 45 kW at 180 rpm with 90 explosions per minute. The change of speed from the commencement to the end of power stroke must not exceed 0.5% of mean on either side. Find the mean diameter of the flywheel and rim cross section having width four times the thickness so that the hoop stress does not exceed 3.5 MPa. Assume that the flywheel stores 6% more energy than the energy stored by the rim and the work done during power stroke is 1.4 times the work done during the cycle. Take density of rim material to be 7300 kg/m^3.
Answer
Sign in to view the complete answer paper.
Derive the expression for friction torque in a flat collar bearing by using uniform pressure and uniform wear conditions.
Answer
Sign in to view the complete answer paper.
Discuss the constructional features of disc type single plate clutch.
Answer
Sign in to view the complete answer paper.
In belt transmission dynamometer, the diameter of the driving and driven pulleys are 0.36 m and 0.8 m respectively. The power transmitted from the driving to the driven shaft is 20 kW. The speed of the driving shaft is 500 rpm. If l=1.2 m and a=400 mm, determine the weight on the lever.
Answer
Sign in to view the complete answer paper.
Discuss the constructional features of hartnell governor.
Answer
Sign in to view the complete answer paper.
Each arm of a porter governor is 300 mm long and is pivoted on the axis of rotation. Each ball has a mass of 6 kg and the sleeve weighs 18 kg. The radius of rotation of the ball is 200 mm when the governor begins to lift and 250 mm when the speed is maximum. Determine the maximum and minimum speeds and the range of speed of the governor.
Answer
Sign in to view the complete answer paper.
Discuss the dunkerley’s method to find the frequency of transverse vibrations.
Answer
Sign in to view the complete answer paper.
A shaft of 40 mm diameter and 2.5 m length has a mass of 15 kg per meter length. It is simply supported at the ends and carries three masses of 90 kg, 140 kg and 60 kg at 0.8 m, 1.5 m and 2 m respectively from the left support. Taking E=200 GN/m^2, find the frequency of the transverse vibrations.
Answer
Sign in to view the complete answer paper.