ISP 205 Lab 3 Discussion Questions

1. How do you calculate the product of two numbers in scientific notation, say 2x105 x 4x103?

How do you calculate the quotient of two numbers in scientific notation, say 2x105 divided by 4x103?

As an application, how do you proceed to calculate the answer to the following questions? If light travels at a velocity of 3x108 m/s and there are 3.6x103 seconds in an hour and approximately 3x107 s in a year, how long does it take light from the Sun to reach Pluto, which is 5.9x109 km from the Sun?

How long does it take for the Sun's light to reach Proxima Centauri, the star closest to the Sun, at a distance of 2.7x105 AU? Note: 1 AU = 1.499x1011 m.

2. Suppose we are visited by sentient life forms from Europa, a moon of Jupiter. The Europans do not know anything about our system of length measurement; however, they tell us that our Moon is 0.57 Hawkings (their unit of astronomical length measure) away from the earth. We know that, in our measurement system, the Moon is 384,405 km from the Earth. It is your task to tell the Europans how many meters there are in a Hawking and how many Hawkings there are in a parsec, an AU, and a light year. How do you set up a unit conversion problem like this and determine the answer? Go step by step.

3. Suppose for a minute that there were no units defined. There are no meters, miles or any other standard distance. You have been called upon for the good of all humanity to devise the standard units of distance that we will use to measure everything. What would you chose for small, medium, and long distances, and why? Would you choose a particular object or item to use as your "standard ruler"? Which ones and why?

4. There are some units in astronomy that are unique to the field such as light-year, parsec, solar mass, solar luminosity, etc. Why do astronomers employ these units ? If we were to invent some units for our use here on Earth, at MSU, what types of units could be created ? How would they help us?

5. You pick up a ticket when you get on a toll road at 10:40am. You travel 193 miles. The speed limit is 80 km/hr. At 1:45 pm, you get off the road and turn in your ticket to pay the proper amount. When you hand the ticket to the attendant, he hands you a court summons for speeding. Why ? Explain. How far have you traveled in km ? What was your average speed in km/hr? Note: 1 km = 0.62 miles

6. Describe what you can learn from the graph below of the distance traveled by a car vs. the elapsed time.

Updated: 2002.09.11 (Wednesday) 10:12:25 EDT