160+ Dynamics of Machines Solved MCQs

101.

Isolation factor is twice the transmissibility ratio.

A. true
B. false
Answer» B. false
102.

The height of a Watt’s governor is

A. directly proportional to speed
B. directly proportional to (speed)
C. inversely proportional to speed
D. inversely proportional to (speed)
Answer» D. inversely proportional to (speed)
103.

A Watt’s governor can work satisfactorily at speeds from

A. 60 to 80 r.p.m
B. 80 to 100 r.p.m
C. 100 to 200 r.p.m
D. 200 to 300 r.p.m
Answer» A. 60 to 80 r.p.m
104.

The ratio of height of Porter governor to the height of Watt’s governor is

A. m/m + m
B. m/ m + m
C. m + m/m
D. m + m/m
Answer» C. m + m/m
105.

When the sleeve of a porter governor moves upwards, the governor speed

A. increases
B. decreases
C. remains unaffected
D. first increases and then decreases
Answer» A. increases
106.

When the sleeve of a Porter governor moves downwards, the governor speed

A. increases
B. decreases
C. remains unaffected
D. first increases and then decreases
Answer» B. decreases
107.

In a Porter governor, the balls are attached to the extension of lower links.

A. true
B. false
Answer» A. true
108.

A Hartnell governor is a

A. dead weight governor
B. pendulum type governor
C. spring loaded governor
D. inertia governor
Answer» C. spring loaded governor
109.

A Watt’s governor is a spring loaded governor.

A. true
B. false
Answer» B. false
110.

Which of the following is a pendulum type governor?

A. watt’s governor
B. porter governor
C. hartnell governor
D. none of the mentioned
Answer» A. watt’s governor
111.

The axis of precession is                          to the plane in which the axis of spin is going to rotate.

A. parallel
B. perpendicular
C. spiral
D. none of the mentioned
Answer» B. perpendicular
112.

A disc is a spinning with an angular velocity ω rad/s about the axis of spin. The couple applied to the disc causing precession will be

A. 1/2 iω2
B. iω2
C. 1/2 iωωp
D. iωωp
Answer» D. iωωp
113.

The engine of an aeroplane rotates in clockwise direction when seen from the tail end and the aeroplane takes a turn to the left. The effect of gyroscopic couple on the aeroplane will be

A. to dip the nose and tail
B. to raise the nose and tail
C. to raise the nose and dip of the tail
D. to dip the nose and raise the tail
Answer» C. to raise the nose and dip of the tail
114.

The engine of an aeroplane rotates in clockwise direction when seen from the tail end and the aeroplane takes a turn to the right. The effect of gyroscopic couple on the aeroplane will be to dip the nose and raise the tail.

A. true
B. false
Answer» A. true
115.

The steering of a ship means

A. movement of a complete ship up and down in vertical plane about transverse axis
B. turning of a complete ship in a curve towards right or left, while it moves forward
C. rolling of a complete ship side-ways
D. none of the mentioned
Answer» B. turning of a complete ship in a curve towards right or left, while it moves forward
116.

The rolling of a complete ship side-ways is known as pitching of a ship.

A. true
B. false
Answer» B. false
117.

The rotor of a ship rotates in clockwise direction when viewed from stern and the ship takes a right turn. The effect of gyroscopic couple acting on it will be to raise the stern and lower the bow.

A. true
B. false
Answer» A. true
118.

The pitching of a ship is assumed to take place with simple harmonic motion.

A. true
B. false
Answer» A. true
119.

When the pitching of a ship is upward, the effect of gyroscopic couple acting on it will be

A. to move the ship towards star-board
B. to move the ship towards port side
C. to raise the bow and lower the stern
D. to raise the stern and lower the bow
Answer» A. to move the ship towards star-board
120.

It is required to lift water at the top of a high building at the rate of 50 litres/min. Assuming the losses due to friction equivalent to 5 m and those due to leakage equal to 5 m head of water, efficiency of pump 90%, decide the kilowatt capacity of motor required to drive the pump.

A. 0.102 kw
B. 0.202 kw
C. 0.302 kw
D. 0.402 kw
Answer» C. 0.302 kw
121.

Power is transmitted by an electric motor to a machine by using a belt drive. The tensions on the tight and slack side of the belt are 2200 N and 1000 N respectively and diameter of the pulley is 600 mm. If speed of the motor is 1500 r.p.m, find the power transmitted.

A. 46.548 kw
B. 56.548 kw
C. 66.548 kw
D. 76.548 kw
Answer» B. 56.548 kw
122.

The flywheel of an engine has a mass of 200 kg and radius of gyration equal to 1 m. The average torque on the flywheel is 1200 Nm. Find the angular acceleration of flywheel and the angular speed after 10 seconds starting from rest.

A. 3 rad/s
B. 4 rad/s
C. 5 rad/s
D. 6 rad/s
Answer» D. 6 rad/s
123.

6 x 10 = 6 rad/s.

A. 2.055 m
B. 3.055 m
C. 4.055 m
D. 5.055 m
Answer» A. 2.055 m
124.

Calculate the work done per minute by a punch tool making 20 working strokes per min when a 30 mm diametre hole is punched in 5 mm thick plate with ultimate shear strength og 450 Mpa in each stroke.

A. 10.69 knm
B. 20.69 knm
C. 30.69 knm
D. 40.69 knm
Answer» A. 10.69 knm
125.

In latitude 25.0 S, SA (spin axis) of a FG (free gyro) is in position S40E and horizontal. Find the tilt after 6 hours.

A. 61.16 up
B. 61.16 down
C. 51.15 up
D. none of the mentioned
Answer» A. 61.16 up
126.

The steering of a ship means

A. movement of a complete ship up and down in vertical plane about transverse axis
B. turning of a complete ship in a curve towards right r left, while it moves forward
C. rolling of a complete ship sideways
D. none of the mentioned
Answer» B. turning of a complete ship in a curve towards right r left, while it moves forward
127.

When the pitching of a ship is upward, the effect of gyroscopic couple acting on it will be

A. to move the ship towards starboard
B. to move the ship towards port side
C. to raise the bow and lower the stern
D. to raise the stern and lower the bow
Answer» A. to move the ship towards starboard
128.

24 m, length of stroke = 0.6 m, length of connecting rod = 1.5 m, mass of reciprocating parts = 300 kg, mass of connecting rod = 250 kg; speed of rotation = 125 r.p.m; centre of gravity of connecting rod from crank pin = 0.5 m ; Kg of the connecting rod about an axis through the centre of gravity = 0.65 m

A. 1.35 m
B. 1.42 m
C. 1.48 m
D. 1.50 m
Answer» B. 1.42 m
129.

24 m, length of stroke = 0.6 m, length of connecting rod = 1.5 m, mass of reciprocating parts = 300 kg, mass of connecting rod = 250 kg; speed of rotation = 125 r.p.m ; centre of gravity of connecting rod from crank pin = 0.5 m ; Kg of the connecting rod about an axis through the centre of gravity = 0.65 m

A. 52.7
B. 49.5
C. 59.5
D. 56.5
Answer» C. 59.5
130.

24 m, length of stroke = 0.6 m, length of connecting rod = 1.5 m, mass of reciprocating parts = 300 kg, mass of connecting rod = 250 kg; speed of rotation = 125 r.p.m; centre of gravity of connecting rod from crank pin = 0.5 m ; Kg of the connecting rod about an axis through the centre of gravity = 0.65 m

A. 16.782
B. 17.824
C. 15.142
D. 17.161
Answer» B. 17.824
131.

24 m, length of stroke = 0.6 m, length of connecting rod = 1.5 m, mass of reciprocating parts = 300 kg, mass of connecting rod = 250 kg; speed of rotation = 125 r.p.m ; centre of gravity of connecting rod from crank pin = 0.5 m ; Kg of the connecting rod about an axis through the centre of gravity = 0.65 m

A. 19000 n
B. 19064 n
C. 19032 n
D. 20064 n
Answer» B. 19064 n
132.

66.

A. 4/3
B. 3/2 c) 3/4
C. d) 1
Answer» B. 3/2 c) 3/4
133.

The starting torque of the steam engine is 1500 N-m and may be assumed constant, using this data find the angular acceleration of the flywheel in rad/s2.

A. 0.4
B. 0.6
C. 0.3
D. 1.2
Answer» B. 0.6
134.

1m then find the other balancing mass situated at a distance of 0.2m.

A. 80
B. 40
C. 20
D. 10
Answer» D. 10
135.

1m. One of the balancing mass is 30 Kg with RoR of 10cm.

A. 70
B. 35
C. 20
D. 10
Answer» B. 35
136.

2m and r=0.3m, l=1m, find l2.

A. 0.26m
B. 0.52m
C. 1.04m
D. 0.13m
Answer» A. 0.26m
137.

2m and r=0.3m, l=1m, find l2.

A. 0.26m
B. 0.52m
C. 1.04m
D. 0.13m
Answer» D. 0.13m
138.

3m, l=1m, find l2 = 0.5m, find r1 in m.

A. 1.5
B. 0.75
C. 3
D. 6
Answer» B. 0.75
139.

2m, 0.15m, 0.25m and 0.3m. Angles between consecutive masses = 45, 75 and 135 degrees.

A. 116
B. 58
C. 232
D. 140
Answer» A. 116
140.

2m, 0.15m, 0.25m and 0.3m. Angles between consecutive masses = 45, 75 and 135 degrees.

A. 201.48
B. 200.32
C. 210.34
D. 202.88
Answer» A. 201.48
141.

The system is automatically statically balanced.

A. 1, 2, 3 and 4
B. 1, 2, and 3 only
C. 2, 3 and 4 only
D. 1, 3 and 4 only
Answer» D. 1, 3 and 4 only
142.

6m c = 2/3

A. 6978
B. 7574
C. 6568
D. 7374
Answer» A. 6978
143.

6m c = 2/3

A. 13956
B. 17574
C. 16568
D. 17374
Answer» A. 13956
144.

6m c = 2/3

A. -6978
B. -7574
C. -6568
D. -7374
Answer» A. -6978
145.

5 kg and the crank radius is 7.5 cm. The length of the connecting rod is 0.3 m. If the engine is rotating at the speed is 500 r.p.m. What is the value of maximum resultant secondary force in Newtons?

A. 736
B. 836
C. 936
D. 636
Answer» B. 836
146.

5 cm. The length of the connecting rod is 0.3 m. If the engine is rotating at the speed is 500 r.p.m. What is the value of maximum resultant secondary force in Newtons?

A. 7172
B. 1672
C. 1122
D. 1272
Answer» B. 1672
147.

5 kg and the crank radius is 7.5 cm. The length of the connecting rod is 0.3 m. If the engine is rotating at the speed is 500 r.p.m. What is the value of maximum resultant secondary force in kN?

A. 2.238
B. 2.508
C. 2.754
D. 2.908
Answer» B. 2.508
148.

6 kN/m and the damping constant of the damper is 400 Ns/m. If the mass is 50 kg, then the damping factor (d ) and damped natural frequency (fn), respectively, are

A. 0.471 and 1.19 hz
B. 0.471 and 7.48 hz
C. 0.666 and 1.35 hz
D. 0.666 and 8.50 hz
Answer» A. 0.471 and 1.19 hz
149.

1 mm.

A. 0.1
B. 0.2
C. 0.5
D. 0.6
Answer» D. 0.6
150.

Calculate the natural longitudinal frequency in Hz.

A. 575
B. 625
C. 525
D. 550
Answer» A. 575
151.

01mm.

A. 44.14
B. 49.85
C. 43.43
D. 46.34
Answer» B. 49.85
152.

Determine the frequency of transverse vibrations of the shaft.

A. 31
B. 35
C. 37
D. 41
Answer» D. 41
153.

Determine the static deflection of the shaft in mm.

A. 0.147
B. 0.213
C. 0.132
D. 0.112
Answer» A. 0.147
154.

665×10-3m, calculate the critical speed of the shaft in rps. Centre of disc at 0.25m away from centre of axis of shaft.

A. 8.64
B. 9.64
C. 10.64
D. 12.2
Answer» D. 12.2
155.

5 m. Find the natural frequency of torsional vibrations.

A. 5.32
B. 5.86
C. 5.65
D. 6.66
Answer» A. 5.32
156.

6m, l2=0.5m, l3=0.4m

A. 8.95
B. 7.95
C. 6.95
D. 5.95
Answer» A. 8.95
157.

85m, kb = 0.55m C = 80 GN/m2

A. 3.37
B. 7.95
C. 6.95
D. 5.95
Answer» A. 3.37
158.

095m, d2=0.06m, d3=0.05m Ma = 900 Kg, Mb = 700 Kg

A. 0.855m
B. 0.795m
C. 0.695m
D. 0.595m
Answer» A. 0.855m
159.

05, 0.06, 0.07.

A. 0.05
B. 0.06
C. 0.07
D. 0.08
Answer» D. 0.08
160.

5m and 70mm in diameter, the middle rotor is at a distance 1.5m from one end. Calculate the free torsional vibration frequency for a single node system in Hz if the mass moment of inertia of rotors in Kg- m2 are: 0.15, 0.3 and 0.09. C=84 kN/mm2

A. 171
B. 181
C. 191
D. 201
Answer» A. 171
161.

5m and 70mm in diameter, the middle rotor is at a distance 1.5m from one end. Calculate the free torsional vibration frequency for a two node system in Hz if the mass moment of inertia of rotors in Kg- m2 are: 0.15, 0.3 and 0.09. C=84 kN/mm2

A. 257
B. 281
C. 197
D. 277
Answer» D. 277
162.

Neglecting the inertia of shaft and gears calculate the frequency of free torsional vibrations in Hz.

A. 4.7
B. 5.7
C. 4.5
D. 5.5
Answer» A. 4.7
163.

5 and the mean speed is 20 rpm, find the maximum speed.

A. 15 rpm
B. 25 rpm
C. 30 rpm
D. 40 rpm
Answer» B. 25 rpm
164.

5 and the mean speed is 20 rpm, find the minimum speed.

A. 15 rpm
B. 25 rpm
C. 30 rpm
D. 40 rpm
Answer» A. 15 rpm
165.

3 m. The engine rotates at 2400 r.p.m. clockwise when viewed from the rear. Find the gyroscopic couple on the aircraft.

A. 10.046 kn-m
B. 11.046 kn-m
C. 12.046 kn-m
D. 13.046 kn-m
Answer» A. 10.046 kn-m
166.

6 m. It rotates at 1800 r.p.m. clockwise, when looking from the stern. Determine the gyroscopic couple, if the ship travels at 100 km/hr and steer to the left in a curve of 75 m radius.

A. 100.866 kn-m
B. 200.866 kn-m
C. 300.866 kn-m
D. 400.866 kn-m
Answer» B. 200.866 kn-m
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