Quiz 16:

1. What is the SI unit of measurement for moment of inertia?

• A. Newton * meter
• B. kilogram * meter
• C. meter * kilogram ²
• D. kilogram * meter ²
• E. kilogram

2. An object is said to be in rotational equilibrium if...

• A. it is either at rest or rotating with a constant angular velocity.
• B. it is either at rest or moving with a constant acceleration
• C. it is either at rest or moving in a straight line with a constant speed.
• D. it is either at rest or moving with a constant speed
• E. it is eithe at rest or rotating with a constant angular acceleration.

3. An object of mass 2.2 kg is revolving in a circular path of radius 7.4 m. Calculate its moment of inertia about an axis of rotation perpendicular to the plane of the circle passing through the center of the circle.

• A. 136.597 kg m²
• B. 156.023 kg m²
• C. 221.014 kg m²
• D. 120.472 kg m²
• E. 72.552 kg m²

4. Three particles of masses 4.3 kg, 10.5 kg and 9.7 kg are located at the points ( -6, -3 ) m, ( -2, -3 ) m, and ( 8, 3 ) m respectively. Calculate the moment of inertia of these system of particles if the axis of rotation is the x-axis.

• A. 255.395 kg m²
• B. 46.47 kg m²
• C. 110.694 kg m²
• D. 392.896 kg m²
• E. 220.5 kg m²

5. Three particles of masses 2.3 kg, 2.5 kg and 9.7 kg are located at the points ( 12, -2 ) m, ( 1, 2 ) m, and ( 8, -1 ) m respectively. Calculate the rotational kinetic energy of this system of particles if they are revolving around the y-axis with an angular velocity of 3 rad ⁄ s.

• A. 6427.685 J
• B. 5610.983 J
• C. 4295.25 J
• D. 7619.251 J
• E. 2224.765 J

6. Three particles of masses 6.3 kg, 3.5 kg and 9.7 kg are located at the points ( 15, -5 ) m, ( 7, 0 ) m, and ( -7, -4 ) m respectively. Calculate the angular momentum of this system of particles if they are revolving around the y-axis with an angular velocity of 18 rad ⁄ s.

• A. 44781.504 J s
• B. 18284.857 J s
• C. 58432.286 J s
• D. 29477.373 J s
• E. 37157.4 J s

7. A spherical object of mass 4 kg and radius 0.014 m is rolling on a horizontal surface with a speed of 0.5 m ⁄ s. Calculate its kinetic energy. ( I_sphere = 2MR ² / 5 )

• A. 0.792 J
• B. 0.7 J
• C. 0.994 J
• D. 0.349 J
• E. 0.258 J

8. A spherical object of mass 2 kg and radius 0.03 m is rolling down an inclined plane of length 1.5 m that makes an angle of 30 deg with the ground. Calculate its speed by the time it reaches the ground( I_sphere = 2MR² / 5 )

• A. 1.292 m ⁄ s
• B. 3.24 m ⁄ s
• C. 0.727 m ⁄ s
• D. 2.81 m ⁄ s
• E. 1.939 m ⁄ s

9. The angular speed of a spherical object revolving about an axis passing through its center increased from 6 rad ⁄ s to 28 rad ⁄ s in 15 s. If its moment of inertia about the axis of roatation is 2.25 kg m ², calculate the torque acting on it.

• A. 4.119 N m
• B. 3.3 N m
• C. 1.838 N m
• D. 5.327 N m
• E. 2.551 N m

10. Two particles of masses 20 kg and 13 kg located at x = 1.4 m and x = -1.8 m on the x-axis (connected by a rod of negligible mass) are revolving about the y-axis with an angular speed of 4.5 rad ⁄ s. If the 20 kg particle slides to the new location x = 0.3, Calculate the new angular speed with which the system is revolving.

• A. 3.733 rad ⁄ s
• B. 8.332 rad ⁄ s
• C. 10.822 rad ⁄ s
• D. 6.292 rad ⁄ s
• E. 9.481 rad ⁄ s