Practice Test 2

Choose the best answer

  1. State Newton's second law.
    1. An object will remain at rest or move in a
      straight line with a costant speed unless
      acted upon by a net force.
    2. Any two objects in the universe attract each
      other with a force directly proportional to
      the product of their masses and inversely
      proportional to the square of the distance
      separating them.
    3. The force acting on an object is inversely
      proportional to the acceleration produced by
      the force.
    4. The force acting on an object is directly
      proportional to the acceleration produced by
      the force.
    5. For every reaction, there is an equal but
      opposite reaction.
    Answer: D

  2. Calculate the force acting on a 6.443 kg object
    moving with an acceleration of 24 m ⁄ s 2.
    1. 126.822 N
    2. 69.669 N
    3. 229.93 N
    4. 154.632 N
    5. 258.491 N
    Answer: D

  3. A force that causes an acceleration of 7 m ⁄ s 2
    on an object of mass 20.123 kg is acting on a
    50 kg object. Calculate the acceleration of the 50 kg object.
    1. 4.167 m ⁄ s 2
    2. 2.817 m ⁄ s 2
    3. 5.069 m ⁄ s 2
    4. 2.412 m ⁄ s 2
    5. 3.399 m ⁄ s 2
    Answer: B

  4. The component of the surface force between two
    surfaces sliding on each other parallel to
    the surface is called
    1. friction
    2. gravitational force
    3. normal force
    4. contact force
    5. sliding force
    Answer: A

  5. An object of mass 48.678 kg is sliding on a horizontal
    surface with a uniform speed. The coefficient
    of kinetic fiction of the surfaces is 0.2. Calculate
    the force of friction exerted by the surface on the object.
    1. 173.387 N
    2. 42.622 N
    3. 95.409 N
    4. 137.284 N
    5. 70.569 N
    Answer: C

  6. An object of mass 18.333 kg is being pulled by a
    horizontal force of 210 N on a horizontal force.
    The coefficient of kinetic friction between
    the object and the surface is 0.45. Calculate the
    acceleration of the object.
    1. 7.045 m ⁄ s 2
    2. 8.396 m ⁄ s 2
    3. 9.969 m ⁄ s 2
    4. 11.447 m ⁄ s 2
    5. 5.149 m ⁄ s 2
    Answer: A

  7. An object is being pulled on a horizontal
    surface by a horizontal force of 300 N.
    If it s moving with a uniform speed, calculate the
    force of friction exerted by the surface on the object.
    1. 30.612 N
    2. 300 N
    3. 3234 N
    4. 360 N
    5. 2940 N
    Answer: B

  8. An object of mass 280 kg is being pulled on a friction less
    horizontal surface by means of two strings. One of the strings
    is pulling forward, has a tension of 600 N and makes
    an angle of 30 degree with the horizontal-right. The other string is
    pulling backwards horizontally and has a tension of 20 N.
    Calculate the acceleration of the object.
    1. 2.05 m ⁄ s 2
    2. 1.784 m ⁄ s 2
    3. 3.218 m ⁄ s 2
    4. 1.176 m ⁄ s 2
    5. 2.351 m ⁄ s 2
    Answer: B

  9. An object of mass 8 kg is being pulled on a horizontal
    surface by a string that makes an angle of
    40 degree with the horizontal. The tension in the string is 17 N.
    Calculate the normal force exerted by the ground on the object.
    1. 67.473 N
    2. 49.729 N
    3. 59.987 N
    4. 27.622 N
    5. 122.067 N
    Answer: A

  10. A 16 kg object and a 7 kg object are
    attached by a string. If the 7 kg object is being pulled
    by a force of 220 N. Calculate their acceleration.
    1. 9.565 m ⁄ s 2
    2. 0.976 m ⁄ s 2
    3. 7.652 m ⁄ s 2
    4. 31.429 m ⁄ s 2
    5. 13.75 m ⁄ s 2
    Answer: A

  11. The SI unit of measurement for work is
    1. Volt
    2. Coloumb
    3. Joule
    4. Pascal
    5. Newton
    Answer: C

  12. An object is being pulled to the left by a 80 N force
    that makes an angle of 70 deg with the horizontal-left
    while moving to the right for a distance of 50 m.
    Calculate the work done by the force.
    1. -1368.081 J
    2. -1094.464 J
    3. 1094.464 J
    4. 1368.081 J
    5. -1641.697 J
    Answer: A

  13. Calculate the speed of an object of mass 42.333 kg
    if its kinetic energy is 1800 J.
    1. 4.521 m ⁄ s
    2. 1.442 m ⁄ s
    3. 13.754 m ⁄ s
    4. 9.222 m ⁄ s
    5. 5.523 m ⁄ s
    Answer: D

  14. Under the influence of some forces, the speed
    of a 21.325 kg object changed from 6 m ⁄ s to a certain speed.
    If the net work done on the object is 1450 J,
    Calculate its final speed.
    1. 13.115 m ⁄ s
    2. 15.634 m ⁄ s
    3. 19.322 m ⁄ s
    4. 7.263 m ⁄ s
    5. 21.714 m ⁄ s
    Answer: A

  15. An object has a kinetic energy of 120 J as it crosses
    a location where its potential energy is 19 J.
    Calculate its mechanical energy as it crosses this location.
    1. 83.4 J
    2. 101 J
    3. 139 J
    4. 111.2 J
    5. 111.1 J
    Answer: C

  16. Under the influence of conservative forces only,
    an object is displaced from point A to point B.
    Its potential energy and kinetc energy at point A are
    respectively 52.666 J and 60.554 J. Its kinetic energy at point B is
    40 J. Calculate its potential energy at point B.
    1. 16.563 J
    2. 114.739 J
    3. 133.294 J
    4. 73.22 J
    5. 85.14 J
    Answer: D

  17. An object of mass 12.333 kg is located at the top
    of a 24 m tall building. Calculate the
    gravitational potential energy of the object
    with respect to a point 1 m below the top
    of the building .
    1. 70.278 J
    2. 120.863 J
    3. 222.484 J
    4. 186.338 J
    5. 45.915 J
    Answer: B

  18. A roller coaster extends to the ground
    from a height of 40 m (point A) and then rises
    to a height of 19 m (point B). An object of mass 2 kg
    starts at point A with a speed of 8 m ⁄ s. Assuming
    the roller coaster is friction less, calculate the
    speed of the object by the time it reaches point B.
    1. 5.494 m ⁄ s
    2. 9.091 m ⁄ s
    3. 2.238 m ⁄ s
    4. 21.808 m ⁄ s
    5. 38.062 m ⁄ s
    Answer: D

  19. A spring extends by 0.8 m when an object of mass
    3 kg hangs from it. By how much will it extend
    when an object of mass 14 kg hangs from it.
    1. 3.001 m
    2. 3.733 m
    3. 1.819 m
    4. 5.291 m
    5. 6.321 m
    Answer: B

  20. Work done by the non conservative forces acting
    on an object is equal
    1. to the change in the mechanical energy of the object
    2. to the change in the kinetic energy of the object
    3. to the work done by the conservative forces
    4. to the change in the potential energy of the object
    5. to the net work done on the object
    Answer: A

  21. Intially an object has a potential energy of 80 J
    and a kinetic energy of 190 J. Under the influence
    of conservative and non-conservative forces
    its potential energy changed to 30 J and its kinetic
    energy changed to 36 J. Calculate the work done
    by the non-conservative forces.
    1. -196 J
    2. -209 J
    3. -204 J
    4. -201 J
    5. -198 J
    Answer: C

  22. Calculate the momentum of an object of mass 0.36 kg
    moving with a speed of 4.8 m ⁄ s.
    1. 1.728 kg m ⁄ s
    2. 0.488 kg m ⁄ s
    3. 1.519 kg m ⁄ s
    4. 2.792 kg m ⁄ s
    5. 1.15 kg m ⁄ s
    Answer: A

  23. An object of mass 0.16 kg falling vertically downward
    hits the ground with a speed of 12 m ⁄ s and bounces
    back vertically upward with a speed 3 m ⁄ s. If the object was in
    contact with the ground for 0.2 seconds, calculate the
    average force exerted by the ground on the object.
    1. 9.933 N
    2. 21.839 N
    3. 12 N
    4. 7.18 N
    5. 16.084 N
    Answer: C

  24. An object of mass 9.5 kg was acted by a force of 24.2 N for
    0.6 seconds. If its initial speed was 2.0 m ⁄ s,
    calculate its final speed.
    1. 1.745 m ⁄ s
    2. 3.528 m ⁄ s
    3. 1.101 m ⁄ s
    4. 4.241 m ⁄ s
    5. 6.311 m ⁄ s
    Answer: B

  25. An object of mass 4 kg moving with a speed
    of 25 m ⁄ s to the right collides with an object
    of mass 17 kg moving with a speed of 12 m ⁄ s
    to the left. After collision, the 17 kg object moves
    to the right with a speed of 9 m ⁄ s to the right. Calculate
    the velocity of the 4 kg object after collision.
    1. -121.326 m ⁄ s
    2. -71.691 m ⁄ s
    3. -103.327 m ⁄ s
    4. -92.482 m ⁄ s
    5. -64.25 m ⁄ s
    Answer: E

  26. An object of mass 16 kg moving with a speed
    of 28 m ⁄ s to the right collides with an object
    of mass 17 kg at rest. If the collision is completely inelastic,
    calculate the kinetic energy lost during the collision.
    1. -3231.03 J
    2. -1009.728 J
    3. -5972.282 J
    4. -4411.118 J
    5. -1871.373 J
    Answer: A

  27. Which of the following statements is a correct
    statement.
    1. Colliding objects always lose kinetic energy
      during collision.
    2. All collisions where momentum is conserved are
      called completely elastic collisions.
    3. If colliding objects are treated as a single
      system, then the net force acting on the
      system is zero.
    4. A collision where both momentum and kinetic
      energy are conserved is called a completely
      inelastic collision.
    5. Kinetic energy is always conserved during a
      collision.
    Answer: C

  28. After a bullet of mass 0.06 kg is fired into a
    ballistic pendulum of mass 1.5 kg, the bullet is embedded
    in the pendulum and the pendulum rose to a height of 0.25 m.
    Calulate the speed with which the bullet was fired into the
    ballistic pendulum.
    1. 57.553 m ⁄ s
    2. 93.151 m ⁄ s
    3. 108.616 m ⁄ s
    4. 41.241 m ⁄ s
    5. 49.171 m ⁄ s
    Answer: A

  29. An object of mass 11 kg going to the right with
    a speed of 30 m ⁄ s collides with a(n) 16 kg object going to
    the left with a speed of 5 m ⁄ s. If the collision
    is completely elastic, calculate the speed of the 16 kg
    object after collision.
    1. 15.128 m ⁄ s
    2. 10.224 m ⁄ s
    3. 21.12 m ⁄ s
    4. 23.519 m ⁄ s
    5. 35.135 m ⁄ s
    Answer: D

  30. An object of mass 21 kg going to the right with
    a speed of 21 m ⁄ s collides with a(n) 10 kg object at rest.
    After collision the 21 kg object moves with a speed of 10 m ⁄ s
    making an angle of 10 degree with the horizontal-right.
    Calculate the x-component of the velocity of the 10 kg
    object after collision.
    1. 38.542 m ⁄ s
    2. 23.419 m ⁄ s
    3. 18.904 m ⁄ s
    4. 30.257 m ⁄ s
    5. 12.274 m ⁄ s
    Answer: B