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Physics 102 Exam 1 Sample
20 February 2002 Prof L. Weinstein

Please give a short explanation for all of your non-numerical answers (unless otherwise noted). Show your work for all numerical answers.
 

Useful numbers: Atmospheric pressure = $10^5$ Pa = 100,000 N/m$^2$

Absolute zero = 0 K = -273 degrees C = -459 degrees F
 
 

  1. (No explanation needed.) In an electrically neutral atom, the number of protons in the nucleus is balanced by the number of (circle all that apply)
    1. neutrons
    2. quarks
    3. orbiting electrons
    4. none of these

     
     
     
     
     
  2. (No explanation needed.) The nuclei of atoms that make up a newborn baby were made in
    1. the mother's womb
    2. the food the mother eats while pregnant
    3. ancient stars
    4. the Earth
    5. other

     
     
     
     
     
  3. (No explanation needed.) Pumice is a rock that floats. Therefore its density is
    1. less than the density of water
    2. greater than the density of water
    3. equal to the density of water
    4. you can't tell

     
     
     
     
     
  4. (No explanation needed.) A balloon is buoyed up with a force equal to the
    1. weight of air it displaces
    2. density of surrounding air
    3. atmospheric pressure
    4. weight of the balloon and its contents
    5. all of these

     
     
     
     
     
  5. How many different elements are in a water molecule (H$_2$O)?

    6.  

     
     
     
     
     

  6. The weight of matter comes mostly from its
    1. protons and neutrons
    2. electrons
    3. other

     
     
     
     
     
  7. Water pressure is greatest against the
    1. top of a submerged object
    2. sides of a submerged object
    3. bottom of a submerged object
    4. is the same against all surfaces
    5. none of these

     
     
     
     
     
  8. What is the buoyant force acting on a 10 ton ship floating in the ocean?
    1. less than 10 tons
    2. more than 10 tons
    3. exactly 10 tons
    4. it depends on the density of seawater
    5. it depends on the shape of the ship

     
     
     
     
     
  9. Two identical buckets are filled to the absolute top with water. One of the buckets has a piece of wood floating in the water. Which bucket weighs more?
    1. The one with the wood
    2. the one without the wood
    3. they weigh the same
    4. need more information

     
     
     
     
     
  10. A large motorboat floats in a swimming pool. If the boat sinks, the water level in the pool will
    1. rise
    2. fall
    3. remain unchanged
    4. need more information

     
     
     
     
     
  11. Air pressure is $10^5$ Pa = 100,000 N/m$^2$. Your frontal surface area is about 0.5 m$^2$. When you are lying down, what is the total mass (in kg or tons) of all the air on top of you?

    12.  

     
     
     
     
     

  12. If there was no atmosphere, would it still be possible to drink water through a straw?

    13.  

     
     
     
     
     
     
     

  13. When a gas in a container is squeezed to half its volume (at constant temperature), its density
    1. quarters
    2. halves
    3. stays the same
    4. doubles
    5. quadruples

     
     
     
     
     
  14. Wind blowing faster over the top of a hill
    1. increases atmospheric pressure there
    2. decreases atmospheric pressure there
    3. does not affect atmospheric pressure there
    4. need more information

     
     
     

  15. Water flows through the wide and narrow pipe as shown. Some of the water squirts upward from tiny leaks at point A (in the wide section) and point B (in the narrow section). The water squirts out fastest (ie: with greatest pressure) at point
    1. A
    2. B
    3. the same at each
    4. need more information

     
     
     
     
     
  16. Compared to a giant iceberg, a hot cup of coffee has
    1. more internal energy and higher temperature
    2. higher temperature but less internal energy
    3. a greater specific heat and more internal energy
    4. none of these

     
     
     
     
     
  17. When water at 4 degrees C is heated it expands. When water at 4 degrees C is cooled by 1 degree it:
    1. expands
    2. contracts
    3. neither expands nor contracts

     
     
     
     
     
  18. The desert sand gets really hot during the day and really cold at night. This indicates that it has a
    1. low specific heat
    2. high specific heat
    3. other (please specify)

     
     
     
     
     
  19. Suppose that you are served hot coffee at a restaurant before you are ready to drink it. The cream is at room temperature. To make sure that the coffee is as hot as possible when you drink it, you should add the cream:
    1. immediately
    2. just before you drink the coffee
    3. it doesn't matter
    4. need more information

     
     
     
     
     
  20. Your feet feel warmer on a rug than on a ceramic tile floor because the rug (circle all that apply)
    1. is usually warmer than the tile
    2. is a better insulator than the tile
    3. for the same mass has more internal energy than the tile
    4. none of these

     
     
     
     
     
  21. A pot of clean snow and a pot of dirty snow are placed on a hot stove. The snow to melt first will be the
    1. clean snow
    2. dirty snow
    3. both the same
    4. need more information

     
     
     
     
     
  22. If you double the pressure of an ideal gas while keeping the temperature constant, the average kinetic energy of the molecules
    1. does not change
    2. increases by less than twice
    3. doubles
    4. more than doubles
    5. need more information

     
     
     
     
     
     
     


2002-02-14