Gravity Questions
What is gravity?
1. What is Newton's law of gravitation? What is the meaning of each variable or constant? What are the limitations of the law in its elementary form?
2. Explain how to measure the radius of the earth, the universal gravitational constant, the acceleration of gravity and the mass of the earth.
3. What is the "International Gravity Formula"? What does each term in the definition signify? Explain what the formula is used for.
4. Define Free Air, simple Bouguer and complete Bouguer anomalies. What is the significance of each term in the definitions?
5. Explain how the three anomalies behave on a regional scale and on a local scale. Which anomaly is preferred for exploration? Explain why.
6. Explain how gravity anomalies support the concept of isostasy.
7. Derive formulae for these simple geometrical bodies: infinite horizontal cylinder, thin vertical cylinder, small cube, small step or fault, sphere, infinite slab and mass ribbon.
8. Explain why we use the vertical component of gravitational attraction in our anomaly calculations.
9. Explain how we can use simple body formulae to interpret gravity anomalies. How can we use them as the foundation of computer programs to model complex 2-D and 3-bodies.
10. Explain how we can measure gravity or gravity differences using free-falling masses, pendulums and gravity meters.
11. Explain several ways to separate regional and residual gravity fields. What are the advantages and disadvantages of each method? In what circumstances would each be preferred?
12. Sometimes we prefer to use various components of the gravity gradient (dg/dx. dg/dz, etc.) rather than gravity itself. What is that so? Discuss in terms of measurement and interpretation.
13. Summarize a case history you have studied. What aspect was most interesting or surprising to you?
14. Compare and contrast gravity methods with other geophysical methods for solving various problems such as...
15. What units do we use to express gravity? How are they related?
16. What units are used to express gravity gradients?
17. Explain how to convert gravity meter readings into gravity anomalies relative to a base station. What data do you need in addition to the meter readings?
18. Explain how to calculate the density of earth materials from mineral densities, fluid densities and porosities.
19. Explain how bore-hole gravity meters can be used to estimate density of strata in wells.
20. Write a good original question to add to this list.