Assignment 1 Reading, Objectives, Problems

Fundamental Physics I [Phys 131] Fall 2004
Assignment #1 Reading, Objectives, & Problems

A. Availability and Due Dates

Assignment #1 is available Tuesday, August 31, 2004. The target date for its successful completion is Thursday, September 9, 2004. In any event, all of the Type A problems from Assignment #1 must be successfully completed and turned in by 5:00 pm on Friday, September 17, 2004. If this requirement is not met, the student will not be allowed to take Quiz 1, to be given in class on Tuesday, September 21, 2004.

B. Reading

As preparation for completing the problems in Assignment #1, read Chapters 1-3 in Cohen's The Fundamentals of College Physics, Volume IA.

C. Objectives

After completing Assignment #1, the student should

Understand what is meant by the terms Theory and Law. Specifically, the student should be able to compare and contrast the two.

Be able to give examples of both Theories and Laws.

Be able to explain what science is to a nonscientist. In particular, the student should be able to distinguish between scientific and non-scientific laws and theories.

Realize that, while it is impossible to prove a theory or law correct, it is possible to disprove one. The student should be able to explain why this is true.

Understand what is meant by the term "testable" when applied to laws and theories. Further, the student should be able to distinguish testable laws and theories from those that are not.

Recognize that science makes predictions by applying general patterns and mechanisms to specific situations.

Understand what a linear relationship is. The student should also be able to give an example of two physical quantities that are related by a linear relationship.

Understand what it means for two variables to be directly proportional. The student should be able to compare this relationship with one in which two variables are linearly related.

Understand what it means for two variables to be inversely proportional.

Understand what it means for two variables to be related quadratically.

Be able to express linear relationships, quadratic relationships, direct proportionality, and inverse proportionality algebraically.

Know what it means for two variables to be independent of one another.

Know what is meant by an empirical relationship. Be able to contrast it with a defined relationship.

Understand what Hooke's Law states, and be able to give examples of situations in which it does and does not hold.

Understand the definition of average speed.

Know the definition of "Pi" in terms of geometric quantities.

Be able to apply the method of Significant Figures to estimate the errors implicit in a calculation.

Know the SI units in which length, mass, time, and force are measured. When presented with any of these quantities expressed in English units, be able to convert to SI units.

Understand and be able to use Scientific Notation.

Understand the content of Newton's Third Law, and be able to apply it. Recognize that Newton's Third Law is "general" in the sense that it applies to all objects in all states of motion. Realize that it is this "general" nature of Newton's Laws that makes them so important.

Understand what a vector is. Understand also what the magnitude and direction of a vector are, and understand how they are represented notationally. In particular, be comfortable with "hat notation".

Understand what is meant by the concept of "Force". Be able to clearly distinguish the concept of "Force" from the concept of "Effect".

D. Type A Problems

[1] Statement 1: Upon death, the spirit of a person is reborn into a new existence.
Statement 2: Protons are composed of three quarks.

The community of Buddhists believes almost uniformly in the first of these statements, while the community of physicists believes almost uniformly in the second. Nevertheless, the statements are not usually viewed on an equal footing. Rather, the first statement is typically referred to as a religious or philosophical statement, while the second is referred to as a scientific statement. What is it about the second statement that makes it scientific, while the first statement is not?

[2] Problem 2.4 on p. 48 of Cohen.
[3] Problem 3.1 on p. 58 of Cohen.
[4] Suppose that some variable, x, is related to three other variables, a, b, and c, in the following way:

Describe how x changes in each of the following cases.

a is doubled

c is doubled

a, b, and c are all doubled

c is cut in half.

[5] The point of this problem is for you to become comfortable with the concepts of distance, displacement, average speed, and average velocity. A car drives due East at 70 mph for 30 minutes, stops for 15 minutes, and then heads due west at 40 mph for 15 minutes.

The distance that the car traveled is defined to be the total amount of ground that it covered, without regard to direction. What total distance did the car travel during the one hour trip?

The displacement of the car is defined to be the difference in position between where it started and where it ended up. What was the car's displacement during the one hour trip?

The average speed of the car is defined to be the distance that it traveled during the trip divided by the trip time. The average velocity, on the other hand, is defined to be the displacement of the car divided by the trip time. Determine the car's average speed and average velocity for the one hour trip.

Is it possible for the average velocity of an object to be larger than its average speed? Explain.

Is is possible for the average velocity of an object to equal its average speed? What would this imply about the motion of the object?

E. Type B Problems

[6] Problem 1.1 on p. 14 of Cohen.
[7] A student proposes the following very simple Law: When water is heated to a temperature of 100° C, it will boil. The student then tests the Law by heating a sample of water to 100° C. As expected, the water boils. Has the student proved the correctness of the Law? Explain.
[8] Give me an example of a theory that is not testable.
[9] Suppose that Chuck requires a daily intake of 2000 calories to maintain weight when not exercising. Further, suppose that Chuck's daily caloric needs increase linearly with the number of hours of exercise that he does. Using C to represent the daily caloric needs of Chuck and h to represent the number of hours that Chuck exercises, write down an algebraic expression showing the relationship between these variables.

Are C and h directly proportional?

[10] Give me an example of an empirical relationship.
[11] Describe a very simple procedure by which you could check whether or not a certain spring obeyed Hook's Law.
[12] Write the result of the calculation (1.09 + 0.011)/(2.6) to the correct number of significant figures.
[13] "The bomb exploded with terrifying force." The usage of the word "force" in this sentence is probably not consistent with the definition of "force" in physics. Explain.