Choose the best answer

1. Which of the following is not a correct
   statement.
   
   1. If colliding objects are treated as a single
      system, then the net force acting on the
      system is zero.
      
   2. The impulse acting on an object is equal to the
      change of momentum of the object.
      
   3. Momentum of colliding objects is always
      conserved.
      
   4. If the net force acting on an object is zero,
      then its momentum is conserved.
      
   5. During a completely elastic collision, some of
      the kinetic energy of the colliding objects
      is converted to heat energy.
      
   Answer: E
   

2. Calculate the momentum of an object of
   mass 18 kg if its kinetic energy is 60 J.
   
   1. 46.476 kg m ⁄ s
      
   2. 57.188 kg m ⁄ s
      
   3. 12.972 kg m ⁄ s
      
   4. 70.713 kg m ⁄ s
      
   5. 38.252 kg m ⁄ s
      
   Answer: A
   

3. After a bullet of mass 0.02 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 0.05 m.
   Calulate the speed of the pendulum just after the collision.
   
   1. 0.99 m ⁄ s
      
   2. 1.843 m ⁄ s
      
   3. 1.504 m ⁄ s
      
   4. 1.196 m ⁄ s
      
   5. 1.353 m ⁄ s
      
   Answer: A
   

4. After a bullet of mass 0.035 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 0.1 m.
   Calulate the speed with which the bullet was fired into the
   ballistic pendulum.
   
   1. 44.806 m ⁄ s
      
   2. 77.114 m ⁄ s
      
   3. 61.4 m ⁄ s
      
   4. 87.099 m ⁄ s
      
   5. 113.496 m ⁄ s
      
   Answer: C
   

5. An object of mass 9 kg going to the right with
   a speed of 12 m ⁄ s collides with a(n) 16 kg object at rest.
   If the collision is completely elastic,
   calculate the speed of the 16 kg object after collision.
   
   1. 15.685 m ⁄ s
      
   2. 1.161 m ⁄ s
      
   3. 12.923 m ⁄ s
      
   4. 2.938 m ⁄ s
      
   5. 8.64 m ⁄ s
      
   Answer: E
   

6. An object of mass 3 kg going to the right with
   a speed of 24 m ⁄ s collides with a(n) 8 kg object going in
   the same direction with a speed of 29 m ⁄ s. If the collision
   is completely elastic, calculate the speed of the 8 kg
   object after collision.
   
   1. 15.631 m ⁄ s
      
   2. 28.958 m ⁄ s
      
   3. 42.49 m ⁄ s
      
   4. 26.273 m ⁄ s
      
   5. 39.738 m ⁄ s
      
   Answer: D
   

7. An object of mass 19 kg going to the right with
   a speed of 21 m ⁄ s collides with a(n) 12 kg object going to
   the left with a speed of 23 m ⁄ s. If the collision
   is completely elastic, calculate the speed of the 12 kg
   object after collision.
   
   1. 30.935 m ⁄ s
      
   2. 35.162 m ⁄ s
      
   3. 8.412 m ⁄ s
      
   4. 22.786 m ⁄ s
      
   5. 41.876 m ⁄ s
      
   Answer: A
   

8. An object of mass 19 kg going to the right with
   a speed of 29 m ⁄ s collides with a(n) 12 kg object at rest.
   After collision the 19 kg object moves with a speed of 19 m ⁄ s
   making an angle of 60 degree with the horizontal-right.
   Calculate the x-component of the velocity of the 12 kg
   object after collision.
   
   1. 46.204 m ⁄ s
      
   2. 53.914 m ⁄ s
      
   3. 19.076 m ⁄ s
      
   4. 22.983 m ⁄ s
      
   5. 30.875 m ⁄ s
      
   Answer: E
   

9. An object of mass 9 kg going to the right with
   a speed of 28 m ⁄ s collides with a(n) 10 kg object at rest.
   After collision the 9 kg object moves with a speed of 20 m ⁄ s
   making an angle of 20 degree with the horizontal-right.
   Calculate the y-component of the velocity of the 10 kg
   object after collision.
   
   1. -0.927 m ⁄ s
      
   2. -6.156 m ⁄ s
      
   3. -8.037 m ⁄ s
      
   4. -2.885 m ⁄ s
      
   5. -5.323 m ⁄ s
      
   Answer: B
   

10. An object of mass 7 kg going to towards north with
    a speed of 28 m ⁄ s collides with a(n) 28 kg object
    going east with a speed of 33 m ⁄ s. After collision
    the 7 kg object moves with a speed of 11 m ⁄ s making
    an angle of 50 degree with the horizontal-right. Calculate
    the magnitude and direction of the velocity of the 28 kg
    object after collision.
    
    1. 39.027 m ⁄ s, 7.431 deg
       
    2. 29.906 m ⁄ s, 8.905 deg
       
    3. 31.613 m ⁄ s, 8.905 deg
       
    4. 28.452 m ⁄ s, 10.102 deg
       
    5. 31.613 m ⁄ s, 10.102 deg
       
    Answer: C