Practice Quiz 16

Choose the best answer

  1. What is the SI unit of measurement for angular
    momentum?
    1. Newton * second
    2. kilogram * meter 2 * rad ⁄ second
    3. Newton * meter ⁄ second
    4. kilogram * rad ⁄ second
    5. kilogram * meter * rad ⁄ second
    Answer: B

  2. An object is said to be in translational equilibrium if
    1. it is either at rest or moving in a straight
      line with a constant speed.
    2. it is eithe at rest or rotating with a constant
      angular acceleration.
    3. it is either at rest or moving with a constant speed
    4. it is either at rest or rotating with a constant
      angular velocity.
    5. it is either at rest or moving with a constant acceleration
    Answer: A

  3. An object of mass 7.3 kg is revolving in a circular
    path of radius 7.4 m with an angular acceleration of
    6.6 rad ⁄ s 2. Calculate the torque acting on the bject
    about an axis perpendicular to the plane of
    the circle passing through the center of
    the circle.
    1. 3432.652 N m
    2. 1881.594 N m
    3. 2638.337 N m
    4. 4786.359 N m
    5. 3769.439 N m
    Answer: C

  4. Three particles of masses 2.3 kg, 1.5 kg and 5.7 kg are located
    at the points ( 12, -4 ) m, ( 1, 5 ) m, and ( 2, -1 ) m respectively.
    Calculate the moment of inertia of these system of particles if
    the axis of rotation is the y-axis.
    1. 355.5 kg m 2
    2. 61.983 kg m 2
    3. 481.504 kg m 2
    4. 601.84 kg m 2
    5. 135.463 kg m 2
    Answer: A

  5. Three particles of masses 6.3 kg, 8.5 kg and 4.7 kg are located
    at the points ( 3, 1 ) m, ( 16, -2 ) m, and ( -4, -4 ) 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 30 rad ⁄ s.
    1. 308390.103 J
    2. 1294833.115 J
    3. 1934667.117 J
    4. 1038555 J
    5. 144792.551 J
    Answer: D

  6. Three particles of masses 7.3 kg, 8.5 kg and 10.7 kg are located
    at the points ( -6, -1 ) m, ( 13, 4 ) m, and ( -4, -3 ) m respectively.
    Calculate the angular momentum of this system of
    particles if they are revolving around the y-axis with
    an angular velocity of 30 rad ⁄ s.
    1. 87875.25 J s
    2. 24716.447 J s
    3. 56115 J s
    4. 33134.061 J s
    5. 16500.744 J s
    Answer: C

  7. A spherical object of mass 5 kg and radius
    0.016 m is rolling on a horizontal surface with
    a speed of 3.5 m ⁄ s. Calculate its kinetic energy.
    ( Ispehre = 2MR 2 / 5 )
    1. 42.875 J
    2. 18.518 J
    3. 24.616 J
    4. 12.897 J
    5. 76.857 J
    Answer: A

  8. A spherical object of mass 2.5 kg and radius
    0.024 m is rolling down an inclined plane of length
    1.5 m that makes an angle of 50 deg with the ground.
    Calculate its speed by the time it reaches the ground
    ( Ispehre = 2MR 2 / 5 )
    1. 4.463 m ⁄ s
    2. 4.011 m ⁄ s
    3. 2.475 m ⁄ s
    4. 3.485 m ⁄ s
    5. 5.445 m ⁄ s
    Answer: B

  9. The angular speed of a spherical object revolving
    about an axis passing through its center increased
    from 3 rad ⁄ s to 29 rad ⁄ s in 17 s. If its moment of inertia
    about the axis of roatation is 0.25 kg m 2, calculate the
    torque acting on it.
    1. 0.297 N m
    2. 0.521 N m
    3. 0.132 N m
    4. 0.08 N m
    5. 0.382 N m
    Answer: E

  10. A skater whose moment of inertia is 5.25 kg m 2 is revolving
    with an angular speed of 5.6 rad ⁄ s. She decreases her
    angular speed to 4.8 rad ⁄ s by extending her hands.
    Calculate her new moment of inertia.
    1. 3.453 kg m 2
    2. 6.125 kg m 2
    3. 8.459 kg m 2
    4. 1.401 kg m 2
    5. 11.176 kg m 2
    Answer: B