Monday, July 9, 2012

Unit 3 - Problem 3 => Gravity on Mt. Everest

Given:

  • $g_{sea-level} = \frac{10\;meters}{seconds^2}$
  • Gravity is inversely proportional to the square of the distance from the center of the earth.
  • The earth's radius is aproximately 6,400 km.
  • Mt. Everest height is about 9 km.
  • Calculate constant of proportionality k.
  • Calculate by what percentage does the acceleration due to gravity change when we stand on Mt. Everest.

Rational for constant of proportionality:

  • $g = \frac{k}{r^2}$

Calculating the constant of proportionality:

  • $10 = \frac{k}{6400^2}$
  • $k = 10*6400^2$

Rational for finding the acceleration due to gravity when we stand on Mt. Everest.

  • Mt. Everest is about 9 km high so its distance from the center of the earth is about 6409 km.
  • $g_{Mt.Everest} = \frac{k}{r^2} = \frac{10*6400^2}{r^2}$

Calculating Mt.Everest force of gravity

  • $g_{Mt.Everest} = \frac{10*6400^2}{r^2}$
  • $g_{Mt.Everest} = \frac{10*6400^2}{6409^2} = 9.971934215130506 = 9.97$

Rational for percent difference:

  • ${percent-difference} = 100 \times \left(\frac{Difference}{{Comparison Value}}\right)$

Calculating the % difference in force of gravity at sea level vs Mt.Everest

  • ${percent-difference} = 100 \times \left(\frac{g_{sea-level}-g_{Mr.Everest}}{g_{sea-level}}\right)$
  • ${percent-difference} = 100*\left(\frac{(10-9.97)}{10}\right)= 0.2999999999999936 = 0.3\;\%$

2 comments:

  1. I do not understand the process used to solve this exercise.

    ReplyDelete
  2. I figured it out. If you are using your phone switch to view as a computer.

    ReplyDelete