1
GATE ME 2009
+1
-0.3
The rotor shaft of a large electric motor supported between short bearings at both the ends shows a deflection of $$1.8$$ mm in the middle of the rotor. Assuming the rotor to be perfectly balanced and supported at knife edges at both the ends, the likely critical speed (in rpm) of the shaft is
A
$$350$$
B
$$705$$
C
$$2810$$
D
$$4430$$
2
GATE ME 2007
+1
-0.3
For an under damped harmonic oscillator, resonance
A
occurs when excitation frequency is greater than undamped natural frequency.
B
occurs when excitation frequency is less than undamped natural frequency
C
occurs when excitation frequency is equal to undamped natural frequency
D
never occurs
3
GATE ME 2006
+1
-0.3
The differential equation governing the vibrating system is
A
$$m\mathop x\limits^{ \bullet \bullet } + c\mathop x\limits^{ \bullet \bullet } + k\left( {x - y} \right) = 0$$
B
$$m\left( {\mathop x\limits^{ \bullet \bullet } - \mathop y\limits^{ \bullet \bullet } } \right) + c\left( {\mathop x\limits^ \bullet - \mathop y\limits^ \bullet } \right) + kx = 0$$
C
$$m\mathop x\limits^{ \bullet \bullet } + c\left( {\mathop x\limits^ \bullet - \mathop y\limits^ \bullet } \right) + kx = 0$$
D
$$m\left( {\mathop x\limits^{ \bullet \bullet } - \mathop y\limits^{ \bullet \bullet } } \right) + c\left( {\mathop x\limits^ \bullet - \mathop y\limits^ \bullet } \right) + k\left( {x - y} \right) = 0$$
4
GATE ME 2005
+1
-0.3
There are four samples P, Q, R and S, with natural frequencies 64, 96, 128 and 256 Hz, respectively. There are mounted on test setups for conducting vibration experiments. If a loud pure not of frequency 144Hz is produced by some instrument, which of the samples will show the most perceptible induced vibration?
A
P
B
Q
C
R
D
S
GATE ME Subjects
EXAM MAP
Medical
NEET