Assignment #2 Reading, Objectives, & Problems
A. Availability and Due Dates
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Assignment #2 is available Tuesday, September 7, 2004. The target date for its successful completion is Thursday, September 16, 2004. In any event, all of the Type A problems from Assignment #2 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
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As preparation for completing the problems in Assignment #2, read Chapters 4 & 5 in Cohen's The Fundamentals of College Physics, Volume IA. |
C. Objectives
After completing Assignment #2, the student should
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Understand Newton's First Law. Further, the student should be able to apply Newton's First Law in physical situations in which it is relevant. |
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Understand the concept of Inertia. Specifically, the student should realize that inertia is not a force. |
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Know what a vector is. The student should realize that "Forces" are vector quantities. |
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Know what a scalar is. The students should be able to contrast scalars with vectors, and should be able to give several examples of vector and scalar quantities. |
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Understand what the term "net" means, especially when used in the context of "Net Force". |
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Understand the concept of "reference frame". |
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Understand what is meant by the term "Inertial Reference Frame", abbreviated IRF. Specifically, the student should be able to describe how observations in a non-inertial reference frame could lead one to believe in forces that don't actually exist. |
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Understand how a vector may be expressed in terms of its magnitude and direction, and know the notation associated with such expression. |
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Understand how a vector may be expressed in terms of components, and know the notation associated with such expression. Further, be able to add and subtract vectors when they are expressed in component form. |
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Given a vector written in terms of magnitude and direction, be able to express it in terms of components. |
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Given a vector written in terms of components, be able to express it in terms of magnitude and direction. |
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Given multiple vectors pointing in arbitrary directions, be able to add them. As a specific application of this technique, be able to add multiple forces to determine the net force acting in an arbitrary physical situation. |
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Know the convention typically used for measuring angles with respect to the coordinate axes, including the interpretation attached to negative angles. |
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Understand Newton's Second Law. Be able to apply Newton's Second Law in physical situations in which it is relevant. |
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Be able to explain why Newton's First and Third Laws are but special cases of the Second Law. |
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Understand the concepts of "average velocity" and "instantaneous velocity". Be able to determine them, given sufficient information. |
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Understand the concept of "average acceleration" and "instantaneous acceleration". Be able to determine them, given sufficient information. |
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Understand the meaning of the geek letter Ä when it sits in front of another symbol. |
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Know that forces are measured in Newtons, and be able to express a Newton in terms of the units kg, m, and s. |
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Understand what a "free-body diagram" is, and be able to construct one given sufficient information. |
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Know that the mass of 1 liter of water at standard temperature and pressure is 1 kilogram. |
D. Type A Problems
[1] Problem 4.3 on p. 96 of Cohen.
[2] Problem 4.7 on p. 97 of Cohen.
[3] Problem 5.2 on p. 122 of Cohen.
[4] Problem 5.5 on p. 122 of Cohen.
[5] Suppose that a bowling ball and a ping-pong ball experience a head-on collision. The mass of the bowling ball is 7 kg, while that of the ping-pong ball is 1 gram.
At one instant during the collision, the acceleration of the bowling ball is 0.1 m/s2 to the right.
(i) What is the net force acting on the bowling ball at this instant in time?
(ii) What is the net force acting on the ping-pong ball at this instant in time?
(iii) What is the acceleration of the ping-pong ball at this instant in time?
E. Type B Problems
[6] Problem 4.2 on p. 96 of Cohen.
[7] Problem 4.5 on p. 96 of Cohen.
[8] Problem 4.6 on p. 96 of Cohen.
[9] Give me examples of three different physical quantities that are vectors, and three other physical quantities that are scalars.
[10] Consider the following two situations:
(A) A car drives down a straight section of road at constant speed.
(B) A car turns a corner at constant speed.
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Do either of these vehicles represent an Inertial Reference Frame? If so, which one(s)? |
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Do either of these vehicles represent a Non-Inertial Reference Frame? If so, which one(s)? |
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If you concluded that either situation above was a non-inertial frame of reference, describe some of the "fictitious" forces that someone riding inside the vehicle might be tricked into believing in. |
[11] Problem 5.4 on p. 122 of Cohen.
[12] Suppose that I first walk North a distance of 150 meters, and then walk west a distance of 75 meters. Determine my total displacement [defined as the difference between where I started and where I ended up]. Remember: my displacement is a vector, and you need to express your answer as a vector.
[13] It is sometimes said that Newton's First Law is already hiding inside of Newton's Second Law. Explain how the first law is implied by the second.
[14] Suppose that a car is driving down a straight road at a constant speed of 85 mph. Draw a free-body diagram for this car, showing clearly all forces acting on the car. What is the net force acting on the car?