Short Answer Questions - Things to Know

Answer the following short questions. Each answer can be an equation, and/or a sentence and/or a diagram. Long answers are not necessary or desirable. These are (for the most part) not like the ones likely to be on a 53 exam, but they are certainly important things to know! In fact, this section contains most of the starting points for the solution of problems you are likely to encounter, as well as the basis for answering most of the short answer, conceptual questions.

1. What is Newton's First Law?

   
   

   
   

   
   

2. What is Newton's Second Law?

   
   

   
   

   
   

3. What is Newton's Third Law?

   
   

   
   

   
   

4. What is the Work-Energy Theorem?

   
   

   
   

   
   

5. What ``force'' makes hurricanes spin anticlockwise in the southern hemisphere?

   
   

   
   

   
   

6. What is ``centrifugal force''?

   
   

7. What is the ``terminal velocity'' of an object in free fall in air?

   
   

8. You may use $g = 10$ m/sec$^2$ (if you wish) throughout this exam. However, show that you know the correct value of $g$ here: $g =$
9. What is Hooke's Law?

   
   

   
   

   
   

10. What is Kepler's first law?

    
    

    
    

    
    

11. What is Kepler's second law?

    
    

    
    

    
    

12. What is Kepler's third law?

    
    

    
    

    
    

13. When is the angular momentum of a system conserved?

    
    

    
    

    
    

14. Write the perpendicular axis theorem. Draw a picture to go with it, if it helps.

    
    

    
    

    
    

15. Write the parallel axis theorem. Draw a picture to go with it, if it helps.

    
    

    
    

    
    

16. What is the definition (either one) of gravitational potential?

    
    

    
    

    
    

17. What is the law of conservation of momentum?

    
    

    
    

    
    

18. What is the fully Generalized Work-energy Theorem (expressed with both conservative and nonconservative forces present)?

    
    

    
    

    
    

19. A golf ball is hit off of the tee. The club is in contact with the ball for a time $\Delta t \approx 10$ msec. How might you estimate the average force exerted by the club on the ball? (Assume that you know or can measure the ball's mass and its speed off of the club.)

    
    

    
    

    
    

20. Qualitatively sketch $P_{\rm av}(\omega)$ for a damped, driven harmonic oscillator with resonant frequency $\omega_0$ and $Q = 10$.

    
    

    
    

    
    

    
    

21. What is the definition of Young's modulus? Draw a picture to illustrate the quantities involved.

    
    

    
    

    
    

22. What is Pascal's Law? A small picture would help.

    
    

    
    

    
    

23. What is Toricelli's Law? How is it derived?

    
    

    
    

    
    

24. What is the Venturi Effect? (Note: In the Physics 53 text, this isn't given by name, but it is covered as the ``Venturi Tube'' and is responsible for the lift of airplane wings and the function of spray mister bottles everywhere).

    
    

    
    

    
    

25. What is the law for thermal expansion of a material?

    
    

    
    

    
    

26. What causes lunar (or solar) tides? Are they (approximately!) the same on the side of the earth facing the moon and the opposite side? Which has the greatest effect on the tide, the sun or the moon?

    
    

    
    

    
    

27. Where is the center of mass of a collection of objects $m_1, m_2, m_3...$ located at $\vec{x}_1, \vec{x}_2, ...$?

    
    

    
    

    
    

28. Write the wave equation (the differential equation) for waves on a string with tension $T$ and mass density $\mu$. Identify all parts.

    
    

    
    

    
    

29. One measures sound intensity in decibels. What is a decibel? (Equation, please, and define all constants.)

    
    

    
    

    
    

30. What is Bernoulli's equation? What does it describe?

    
    

    
    

    
    

31. What is the ``0th'' Law of Thermodynamics?

    
    

    
    

    
    

32. What is the 1st Law of Thermodynamics?

    
    

    
    

    
    

33. What is the 2nd Law of Thermodynamics (any form, extra points for more than one).

    
    

    
    

    
    

34. What is the ``3rd'' Law of Thermodynamics.

    
    

    
    

    
    

35. What is the Equipartition Theorem?

    
    

    
    

    
    

36. When is a force a ``conservative force''? What is being conserved?

    
    

    
    

    
    

37. What is Archimedes' Principle?

    
    

    
    

    
    

38. Suppose a heat engine is operating between two reservoirs: one is at $T_c = 300$ $^\circ$K, the other is at $T_h = 600$ $^\circ$K. What is the highest its efficiency could be?

    
    

    
    

    
    

39. What are the four ``fundamental'' forces of nature?

40. A pitcher throws a ball at home plate with backspin (that is, bottom of the ball is moving toward the direction of motion, the top away as it rotates). Does the pitch tend to rise or fall? Why? (Draw picture)

    
    

    
    

    
    

    
    

    
    

    
    

41. Roman soldiers (like soldiers the world over) marched in step - except when crossing bridges, when they broke the march and walked over with random pacing. Why?