Problems 1, 3, 5, 7, p 312-13
1. Use the speed of light and number of seconds
in a year. Assume 1 year = exactly 365 days
3. Report this distance in meters or kilometers.
Once again you need the time in seconds as
in #1;
5. Use proportion; ratio of one intensity
to the square of its distance equals ratio
of other intensity to square of its distance.
Equation is found on p 312 (ans: 21 cd)
7. Use same equation as in #5. If the distance
from one of the lights to the screen is x the distance to the other will be (100 cm
- x). Substitute these values into the equation,
simplify algebraically and put into quadratic
equation form ax2+bx+c=0 . Solve using the quadratic formula. One
root is impossible (545 cm) so the other
root is the answer.
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