JQuiz Instructions

1. A 200 kg lineman moves 7 m/s. What is his momentum?

   1.   ?    28.6 kg s/m
   2.   ?    1400 kg m/s
   3.   ?    .07 kg m/s

2. What work is done in lifting a 400 N weight to a height of 20 m?

   1.   ?    .05 m/n
   2.   ?    20 N/m
   3.   ?    8000 J

3. What work is required to lift a 20 kg mass to a height of 12 meters?

   1.   ?    240 Nm
   2.   ?    240 kg m
   3.   ?    2400 J

4. How much kinetic energy does a 5 kg mass traveling at 12 m/s have?

   1.   ?    60 kg m/s
   2.   ?    720 J
   3.   ?    .41 kg/s2
   4.   ?    360 J

5. How much work is done against friction if a 200 N force keeps a car rolling at constant speed across a level parking lot for a distance of 12 meters?

   1.   ?    .06 m/N
   2.   ?    16.7 N/m
   3.   ?    0 J
   4.   ?    360 J

6. Choose two ways that allow for the determination of the speed that an object falling from rest has before it hits the ground.

   1. Multiply its speed at the outset by its time in the air.
   2. Use its height in the air to find its potential energy, then set that equal to the kinetic energy at landing and calculate the only remaining unknown -- velocity
   3. Use a kinematic relationship: vf2 = vi2 + 2ad
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7. How fast is any object moving (as it hits the ground) if it falls 125 meters without air resistance to the ground? (g = 10 m/s/s)

   1.   ?    125 m/s
   2.   ?    25 m/s
   3.   ?    50 m/s
   4.   ?    100 m/s

8. In which cases is mechanical energy not conserved?

   1. Where friction is considered
   2. In an inelastic collision
   3. In an elastic collision
   4. Mechanical energy is always conserved
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9. A 50 N net force acts on a 100 kg motorcycle that comes to rest in 20 seconds. What is the original velocity of the motorcycle? Answer with no units (they are of course m/s).

   
   
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10. For how long will a 75 N force have to act on a 50 Kg mass moving 25 m/s in order to stop it? (round to the nearest whole second)

    
    
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11. A 50 kg skateboarder at rest, faces a 100 kg skateboarder also at rest. If the smaller boarder pushes the larger with a certain force, the large will move east at 12 m/s. What happens to the smaller skater?

    1.   ?    east at 12 m/s also
    2.   ?    west at 12 m/s
    3.   ?    west at 6 m/s
    4.   ?    west at 24 m/s

12. How do you maximize torque.

    1.   ?    long lever arm and large force
    2.   ?    short lever arm and small force
    3.   ?    short lever arm and large force
    4.   ?    long lever arm and small force

13. Two resisters are in series with a 12 volt battery (one 1 ohm and the other 2 ohms). In order, what is the potential drop across the 1 and 2 ohm restances?

    1.   ?    1 V, 2 V
    2.   ?    12 V, 12 V
    3.   ?    4 V, 8 V
    4.   ?    8 V, 4 V

14. What current does a 12 V cell drive through a circuit with a 1 ohm and a 2 ohm restance in series?

    1.   ?    12 A
    2.   ?    6 A
    3.   ?    3 A
    4.   ?    4 A

15. What happens to the force between two charged objects if we double the distance between them?

    1.   ?    it halves
    2.   ?    it doubles
    3.   ?    it triples
    4.   ?    it is reduced to 1/4 th its original value

16. What happens if we increase the distance between charged objects by multiplying it by 5?

    1.   ?    25 times
    2.   ?    1/25
    3.   ?    5 times
    4.   ?    1/5

17. If A is inversely proportional to the square of B and if A is 96 when B is 4, what is A when B is 2?

    
    
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18. If A is inversely proportional to the square of B and if A is 96 when B is 4, what is A when B is 8?

    
    
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19. Convert 5 radians per second into revolutions per second. Round to the hundredth of a revolution. Omit units (rev/s)

    1.   ?    .80
    2.   ?    0.80

20. Convert 5 rev/s to radians per second. Record to 1/10th radian. Omit unit.

    1.   ?    31.4