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Name: ______________________________ Physics Chapter 1 Section Reviews Section 1: 1. What are the steps you might use to carry out an investigation using scientific methods? a. o___________________ : b. r___________________ : c. h___________________ : d. e___________________ : e. r___________________ : f. v___________________ : g. r___________________ : h. (if hypothesis is not supported) m___________________ : 2. Differentiate between a hypothesis and a scientific theory. 3. How can bias affect the outcome of scientific research? 4. Give three examples of models used by scientists (different sorts of models), and explain why each is useful. a. b. c. 5. A scientist conducts a survey in which he or she asked students in your school about lunches provided by the cafeteria and finds that 90 percent of the students surveyed like pizza. The scientist then concludes that this scientifically proves that everyone likes pizza. Is this conclusion valid? Why or why not? 6. Section 2: 7. 8. An accepted value for free-fall acceleration is 9.8 m/s2. In an experiment with pendulums, you calculate that the value is 9.4 m/s2. Should the accepted value be tossed out to accommodate your new finding? Explain why it should or should not. Why are concepts in physics described with mathematical formulas? What is the primary reason that scientists must use SI units in their research? 9. How many kilohertz are 750 megahertz? 10. How many seconds are in a leap year? 11. Solve the following problems using the correct number of significant figures each time. a. 10.8 g – 8.264 g = ____________ b. 4.75 m – 0.4168 m = ____________ c. 139 cm X 2.3 cm = ____________ d. 13.78 g / 11.3 mL = ____________ e. 6.201 cm + 7.4 cm + 0.68 m + 12.0 cm = __________ f. 1.6 km + 1.62 m + 1200 cm = ____________ 12. Rewrite F = Bqv to find v in terms of F, q and B. (Change the equation so that it is v = ??? instead of using mathematical operations.) F = ???, 13. Using values given in a problem and the equation of distance = speed X time (d = rt or d = st), you calculate a car’s speed to be 280 km/h. Is this a reasonable answer? Explain why or why not, and if it is, tell what circumstances might be occurring in order for the car to travel at this speed. Section 3: 14. You find a micrometer (a tool used to measure objects to the nearest 0.001 mm) that has been badly bent. How would it compare to a new, high-quality meterstick in terms of its precision and its accuracy? 15. In order to improve their accuracy, some wooden rulers do not start with 0 at the actual edge, but instead have it set in a few millimeters. How does this improve the accuracy of the ruler, assuming the user is competent? 16. Your friend tells you his height is 182 cm. In your own words, explain the range of heights allowed by this statement. (Think significant figures!) 17. A box has a length of 18.1 cm and a width of 19.2 cm, and it is 20.3 cm tall. a. What is its volume? b. How precise is the measurement of length? c. How precise is the measurement of volume? d. How tall is a stack of 12 of these boxes? e. How precise is the measurement of the height of one box? f. How precise is the measurement of the height of 12 boxes? 18. Your friend states in a report that the average time required for a car to circle a 1.5-mi track was 65.414 s. This was measured by timing 7 laps using a clock with a precision of 0.1 s. How much confidence do you have in the results of the report? Explain.