Try these practice problems, and click on the
"Answer" link to check your work.
1. 
Light travels at approximately
3.0 x 10^{8
} m/sec.
How far does light
travel in one week?


Answer 
2. 
Assume that there are 20,000 runners in the New York City Marathon.. Each runner runs a distance
of 26 miles. If you add together the total number of
miles for all runners, how many times around the globe would the
marathon runners have gone?
Consider the circumference of the earth to be 2.5 x 10^{4}
miles.


Answer

3. 
Mercury's average distance from the sun is 57,910,000 km.
The Earth is approximately 93,000,000 miles from the sun.
What would be the distance of a trip from Mercury to Earth, via
the Sun. Look out for the units!!!
(1 km = 0.62 mi)
Use Scientific
Notation to solve this question.


Answer 

4. 
One of the fastest supercomputers in the world is
NEC's Earth Simulator, which operates at a
topend of 40 teraflops (forty trillion operations per second).
How long would it take this computer to perform 250
million calculations?


Answer

5. 
The halflife of Uranium
234 is 2.5 x 10^{5} years and the halflife of Plutonium is 8.0
x 10^{7} years. How
many times greater is the halflife of Plutonium than Uranium 234?


Answer

6. 
The Earth is approximately 93,000,000 miles from the sun. How
long does it take light from the sun to reach the earth? Use the
speed of light to be 1.86 x 10^{5} miles per second.


Answer

7. 
Light travels at a speed of 1.86 x 10^{5} miles per second.
If a "light year" is the distance that light travels in one
year, how many miles are in a light year?


Answer

