## GATE ME Solved Questions on Flywheels(Theory of Machines)

Question #1

Consider a slider crank mechanism with nonzero masses and inertia. A constant torque τ is applied on the crank as shown in the figure. Which of the following plots best resembles variation of crank angle, θ versus time

[GATE 2015 S1, 1 mark]

Question #2

The torque (in N-m) exerted on the crank shaft of a two stroke engine can be described as $T=10000+1000sin2\theta-1200cos2\theta$, where $\theta$ is the crank angle as measured from inner dead center position. Assuming the resisting torque to be constant, the power (in kW) developed by the engine at 100 rpm is ________

[GATE 2015 S3, 2 marks]

Question #3

Maximum fluctuation of kinetic energy in an engine has been calculated to be 2600 J. Assuming that the engine runs at an average speed of 200 rpm, the polar mass moment of inertia (in kg.m2 ) of a flywheel to keep the speed fluctuation within ±0.5% of the average speed is _______

[GATE 2014 S2, 2  marks]

Question #4

Consider a flywheel whose mass M is distributed almost equally between a heavy, ring-like rim of radius R and a concentric disk-like feature of radius R/2. Other parts of the flywheel, such as spokes, etc, have negligible mass. The best approximation for $\alpha$, if the moment of inertia of the flywheel about its axis of rotation is expressed as$\alpha MR^2$ , is _______

[GATE 2014 S2, 2  marks]

Question #5

Torque and angular speed data over one cycle for a shaft carrying a flywheel are shown in the figures. The moment of inertia (in kg.m2 ) of the flywheel is _______

[GATE 2014 S4, 2 marks]

Question #6

A flywheel connected to a punching machine has to supply energy of 400 Nm while running at a mean angular speed of 20 rad/s. If the total fluctuation of speed is not to exceed ±2%, the mass moment of inertia of the flywheel in kg-m2 is

(A) 25

(B) 50

(C) 100

(D) 125

[GATE 2013, 2 marks]

Question #7

circular solid disc of uniform thickness 20 mm, radius 200 mm and mass 20 kg, is used as a flywheel. If it rotates at 600 rpm, the kinetic energy of the flywheel, in Joules is

(A) 395

(B) 790

(C) 1580

(D) 3160

[GATE 2012,  1 mark]

Question #8

The speed of an engine varies from 210 rad/s to 190 rad/s. During cycle the change in kinetic energy is found to be 400 Nm. The inertia of the flywheel in kgm

(A) 0.1

(B) 0.2

(C) 0.3

(D) 0.4

[GATE 2007, 2 marks]

Question #9

If Cf  is the coefficient of speed fluctuation of a flywhel then the ratio of  $\omega _{max}/\omega _{min}$ will be

(A) $\frac{1-2C_f}{1+2C_f}$

(B) $\frac{2-2C_f}{2+C_f}$

(C) $\frac{1-2C_f}{1-2C_f}$

(D) $\frac{2+C_f}{2-C_f}$