Practice Final exam

Choose the best answer

  1. How many uncertain digits can a report of a
    measurement have?
    1. 4
    2. 1
    3. 2
    4. 3
    Answer: B

  2. Use dimensional analysis to determine which of
    the following equations is dimensionally
    correct
    1. time 2 = distance ⁄ speed 2
    2. time 2 = distance ⁄ acceleration
    3. time 2 = acceleration ⁄ speed
    4. time 2 = speed ⁄ acceleration
    5. time 2 = acceleration ⁄ distance
    Answer: B

  3. The following is the graph of position versus time for a certain particle.



    Calculate the average velocity for the first 4 seconds.
    1. 4 m ⁄ s
    2. 0.5 m ⁄ s
    3. 2 m ⁄ s
    4. 1 m ⁄ s
    5. 0 m ⁄ s
    Answer: D

  4. The speed of a uniformly ccelerated particle changed
    from 400 m ⁄ s to 1300 m ⁄ s in a distance of 2050 m.
    Its acceleration and the time taken respectively are
    1. 373.171 m ⁄ s 2 and 2.412 s
    2. 0.22 m ⁄ s 2 and 1.206 s
    3. 0.22 m ⁄ s 2 and 2.412 s
    4. 451.22 m ⁄ s 2 and 1.206 s
    5. 373.171 m ⁄ s 2 and 1.206 s
    Answer: A

  5. The default angle (angle measured with respect to the positive x-axis) for
    the vector A = 2 m west is
    1. 0 deg
    2. 180 deg
    3. -90 deg
    4. 90 deg
    5. 270 deg
    Answer: B

  6. A bullet is fired from the ground making an angle of 20 deg
    with the horizontal with a speed of 1400 m ⁄ s.
    How far (horizontally) will it fall?
    1. 80827.062 m
    2. 128557.522 m
    3. 239321.318 m
    4. 105402.096 m
    5. 62345.45 m
    Answer: B

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

  8. A 10 kg object and a 11 kg object are
    attached by a string. If the 11 kg object is being pulled
    by a force of 240 N. Calculate their acceleration.
    1. 9.143 m ⁄ s 2
    2. 1.166 m ⁄ s 2
    3. 21.818 m ⁄ s 2
    4. 11.429 m ⁄ s 2
    5. 24 m ⁄ s 2
    Answer: D

  9. Under the influence of conservative forces only,
    an object of mass 9 kg is displaced from
    point A to point B. Its potential energy and speed at point A
    respectively are 850 J and 22 m ⁄ s. Its potential energy at point B is -100 J.
    Calculate its speed at point B.
    1. 26.365 m ⁄ s
    2. 39.36 m ⁄ s
    3. 32.807 m ⁄ s
    4. 47.268 m ⁄ s
    5. 22.254 m ⁄ s
    Answer: A

  10. Which of the following is a correct statement?
    1. Work done by non conservative forces is equal to
      the change in the kinetic energy of the object.
    2. Net work done on an object is equal to the
      change in the mechanical energy of the object.
    3. Net work done on an object is equal to the
      change in the kintic energy of the object
    4. Work done by conservative forces is equal to the
      change in the kinetic energy of the object.
    5. Work done by conservative forces is equal to the
      change in the mechanical energy of the object.
    Answer: C

  11. The rate of change of momentum with time of an
    object is equal to
    1. the acceleration of the object
    2. the mechanical energy of the object
    3. the kinetic energy of the object
    4. the potential energy of the object
    5. the force acting on the object
    Answer: E

  12. Calculate the momentum of an object of
    mass 12 kg if its kinetic energy is 10 J.
    1. 12.796 kg m ⁄ s
    2. 26.048 kg m ⁄ s
    3. 2.087 kg m ⁄ s
    4. 23.465 kg m ⁄ s
    5. 15.492 kg m ⁄ s
    Answer: E

  13. An object is revolving in a circular path of
    radius 4 m with a uniform speed. If it makes
    19 cycles per second, calculate its
    centripetal acceleration.
    1. 91257.367 m ⁄ s 2
    2. 22523.785 m ⁄ s 2
    3. 79359.429 m ⁄ s 2
    4. 51052.565 m ⁄ s 2
    5. 57006.835 m ⁄ s 2
    Answer: E

  14. A wheel of radius 6 m was rolled for a distance
    of 40 m. Calculate the angular displacement
    of a point on the rim of the wheel.
    1. 4.917 rad
    2. 7.961 rad
    3. 12.468 rad
    4. 1.841 rad
    5. 6.667 rad
    Answer: E

  15. A uniform horizontal lever of length 4.8 m is
    pivoted at its mid-point. The following forces
    are acting on the lever: a 0.23 N vertically upward force
    acting at the right end of the lever, a 2 N
    vertically upward force acting at the left end of the
    lever, and a 11 N vertically downward force acting at a
    point on the lever 0.9 m away from the right end.
    Calculate the net torque acting on the lever.
    1. -27.581 N m
    2. -3.683 N m
    3. -20.748 N m
    4. -21.852 N m
    5. -30.898 N m
    Answer: C

  16. Three particles of masses 7.3 kg, 2.5 kg and 10.7 kg are located
    at the points ( -12, 3 ) m, ( -5, 5 ) m, and ( 14, -3 ) m respectively.
    Calculate the moment of inertia of these system of particles if
    the axis of rotation is the x-axis.
    1. 224.5 kg m 2
    2. 347.939 kg m 2
    3. 22.869 kg m 2
    4. 115.476 kg m 2
    5. 318.334 kg m 2
    Answer: A

  17. An aluninum wire has a length of 3 m and a
    cross-sectional radius of 0.003 m. Calculate the change in
    its length when an object of weight 90 N hangs from the wire.
    (modulus = 7e10 Pa)
    1. 1.518e-5 m
    2. 15.731e-5 m
    3. 3.782e-5 m
    4. 13.642e-5 m
    5. 5.549e-5 m
    Answer: D

  18. Calculate the density of an object that floats in a fluid
    of density 2500 kg ⁄ m 3 with 50 % of its volume
    immersed in the fluid.
    1. 2072.601 kg ⁄ m 3
    2. 1434.317 kg ⁄ m 3
    3. 1852.326 kg ⁄ m 3
    4. 1250 kg ⁄ m 3
    5. 797.438 kg ⁄ m 3
    Answer: D

  19. An aluminum rod has a length of 1 m at a
    temperature of 20 �C. What should its temperature
    be if its length is to increase by 0.004 m. (Coefficient of
    linear expansion for aluminum is 2.4e-5 ⁄ �C).
    1. 291.783 �C
    2. 138.514 �C
    3. 42.416 �C
    4. 186.667 �C
    5. 118.644 �C
    Answer: D

  20. A gas in a balloon has a volume of 6 L at a pressure
    of 90 kPa. Calculate its volume when its pressure
    is changed to 45 kPa at constant temperature.
    1. 17.328 L
    2. 12 L
    3. 9.52 L
    4. 13.866 L
    5. 8.216 L
    Answer: B

  21. Calculate the heat energy required to melt 8 kg
    of ice (Latent heat of fusion 3.34e5 J ⁄ kg).
    1. 2672000 J
    2. 3376316.722 J
    3. 1905304.128 J
    4. 2186520.004 J
    5. 1422067.935 J
    Answer: A

  22. Conduction is a way of transfer of heat
    1. by means of movement of air molecules.
    2. by means of collisions of neighboring molecules.
    3. by means of the actual movement molecules.
    4. by means of emission of particles.
    5. by means of propagation of electromagnetic waves.
    Answer: B

  23. The following is a PV dagram for a certain system of gas.



    Calculate the work done in taking the system from the point C( 6 L, 4 kPa)
    to the point A( 2 L, 2 kPa) along path CDA.
    1. 24 J
    2. -8 J
    3. -16 J
    4. 8
    5. 16 J
    Answer: C

  24. A heat engine absorbs 1600 J of energy
    from a hot reservior at a temperature of 380 �C
    and gives off 760 J of energy to a cold
    reservior at a temperature of 32 �C in a cyclic process.
    Calculate the amount of work done per cycle.
    1. 0
    2. 1220 J
    3. 1980 J
    4. 2360 J
    5. 840 J
    Answer: E