Physics 173 Internet Question of the Week

The Questions

February 16 - February 20, 1998

Question #1:

We are finishing up a unit titled "Newton's Laws and Vectors Applications" and will soon be starting a unit titled "Circular and Planetary Motion." In a sense, the next unit could also be titled Newton's Laws and Vectors Applications to Circular Motion. This week's questions of the week will prepare you for the vector/force aspect of the next unit by browsing two sites which focus on the motion of objects in a circle. The sites which you will browse are The Physics Classroom and the Multimedia Physics Studios. These two sites are actually located at the same site - which happens to be a high school site. Use a major search engine to find either The Physics Classroom or the Multimedia Physics Studios. The most useful search engines to use for this task are HotBot (, Lycos ( and Alta Vista ( If you find The Physics Classroom, then navigate to the Multimedia Physics Studios using the links from that page. (If you already know the location of these sites, then of course it is not necessary to use the search engines.)

Once you have found the homepage of the Multimedia Physics Studios, do the following:

  1. Identify the URL (address) of the home page of the Multimedia Physics Studios.
  2. Describe the search path which you took to find the page (see example description).
  3. Browse through the homepage and look at the variety of animations under the topic of Circular and Satellite Motion. (NOTE: if you have an outdated AOL browser and haven't updated recently, then you probably won't be able to view the animations. Use the Internet connection at the school or get an updated browser from AOL.) Search through a sufficient number of animations until you find the answers to the following questions. (Do a bang-up job on this question; it is worth two of the three extra credit points. Besides, by learning well, you will be prepared for the upcoming unit.)
    1. Describe the connection between Newton's first law and the motion of an object in a circle. Cite the address of the page upon which you found this answer.
    2. We will be concerned with several motion characteristics for objects moving in a circle: most specifically, the velocity, the acceleration, and the net force. View an animation and determine the direction of each of these vector quantities for an object moving in a circle. Cite the address of the page upon which you found this answer.
    3. Explain how a free-body diagram can be used to determine the size of the normal force compared to the size of the gravitational force for a roller coaster car moving through a circular loop. Cite the address of the page upon which you found this answer.
    4. Explain how an orbitting satellite is like a projectile. Cite the address of the page upon which you found this answer. Cite the address of the page upon which you found this answer.


Question #2:

A 80-gram object is attached to a 200-gram air track glider by a light string. The 80-gram object is suspended over a pulley. The air track is inclined at an angle of 20 degrees. The air track is turned on and the glider accelerates along the track. Construct a diagram of this situation and then calculate the acceleration of the glider and the distance it moves in 0.75 seconds. (CAUTION: pay attention to units.) PSAYW


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Last Updated: February 13, 1998