Question 1

A flywheel has a mass of 20 kg and a radius of gyration of 100 mm. Its angular kinetic energy when rotating at 10 rev/s is:

Accepted Answer

A)  2J 
B)  20J 
C)  790J 
D)  7896J 
A)  2J 
B)  20J 
C)  790J 
D)  7896J C

Question 2

If the moment of inertia of a slender rod of length L and mass m about an axis through its centre is mL2/12, then its moment of inertia about an end is:

Accepted Answer

A)  mL2/12 
B)  mL2/3 
C)  mL2 
D)  13mL2/12 
A)  mL2/12 
B)  mL2/3 
C)  mL2 
D)  13mL2/12 B

Question 3

Decide whether each of these statements is True (T) or False
A flywheel has a moment of inertia of 40 kg m2 about its axis and is at rest when a constant torque of 90 N m is applied. After 15 s:

Accepted Answer

A)  (i) T (ii) T 
B)  (i) T (ii) F 
C)  (i) F (ii) T 
D)  (i) F (ii) F 
A)  (i) T (ii) T 
B)  (i) T (ii) F 
C)  (i) F (ii) T 
D)  (i) F (ii) F A

Question 4

The rotor of a motor is accelerated from rest by a torque of 250 N m. When it has rotated through 10 revolutions, the gain in angular kinetic energy is:

Accepted Answer

A)  2.5kJ 
B)  5.0kJ 
C)  7.85kJ 
D)  15.7kJ 
A)  2.5kJ 
B)  5.0kJ 
C)  7.85kJ 
D)  15.7kJ

Question 5

The constant torque required to get a wheel of moment of inertia about its axle of 100 kg m2, starting from rest, to rotate at 5 rev/s after 15 s is:

Accepted Answer

A)  14.0 Nm 
B)  39.6 Nm 
C)  209 Nm 
D)  3142 Nm 
A)  14.0 Nm 
B)  39.6 Nm 
C)  209 Nm 
D)  3142 Nm

A flywheel has a mass of 20 kg and a radius of gyration of 100 mm. Its angular kinetic energy when rotating at 10 rev/s is:

If the moment of inertia of a slender rod of length L and mass m about an axis through its centre is mL2/12, then its moment of inertia about an end is:

Decide whether each of these statements is True (T) or False A flywheel has a moment of inertia of 40 kg m2 about its axis and is at rest when a constant torque of 90 N m is applied. After 15 s:

The rotor of a motor is accelerated from rest by a torque of 250 N m. When it has rotated through 10 revolutions, the gain in angular kinetic energy is:

The constant torque required to get a wheel of moment of inertia about its axle of 100 kg m2, starting from rest, to rotate at 5 rev/s after 15 s is:

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Exam 15: Angular Dynamics

A flywheel has a mass of 20 kg and a radius of gyration of 100 mm. Its angular kinetic energy when rotating at 10 rev/s is:

If the moment of inertia of a slender rod of length L and mass m about an axis through its centre is mL2/12, then its moment of inertia about an end is:

Decide whether each of these statements is True (T) or False A flywheel has a moment of inertia of 40 kg m2 about its axis and is at rest when a constant torque of 90 N m is applied. After 15 s:

The rotor of a motor is accelerated from rest by a torque of 250 N m. When it has rotated through 10 revolutions, the gain in angular kinetic energy is:

The constant torque required to get a wheel of moment of inertia about its axle of 100 kg m2, starting from rest, to rotate at 5 rev/s after 15 s is:

Basics, and Statics

Linear Motion, and Stress and Strain

Angular Motion

Dynamics, and Energy

Heat, and D.C Circuits

Capacitance, and Magnetic Flux

Alternating Current, and Series A.C Circuits

Transients, D.C Circuit Analysis, and D.C Machines

Parallel A.C Circuits

Three-Phase A.C

Circular Motion, Component, and Structures

Mechanical Power Transmission

Structural Members

Frictional Resistance

Oscillations

Filters