Chapter 5: Rational Expressions
Numbers in the Real World

Weight Loss
 

The mass of a body is the measurement of the amount of matter it contains. Inertia is the resistance of a body to motion from rest or to rest from motion. Mass is a measure of the amount of inertia in a body.

Weight, on the other hand, is the measurement of the amount of attraction between two masses. This force of attractions is dependent upon the size of the two masses and the distance between them. We use scales to measure our weight here on Earth, the amount of force of attraction between the Earth and us. Isaac Newton recognized this relationship (that we call weight) due to gravity and published the Law of Gravity in 1687.

So how do you lose weight, the variable F in the formula above? You must diminish your mass, diminish the mass of the larger object, increase the distance between the two, or a combination of these.

What if the Earth was smaller in diameter but contained the same mass? Would your weight increase?
You should have answered yes. The distance in the formula is the measurement from the center of the mass. Therefore, the distance would be smaller since the radius would be smaller.

I took a trip to each of the planets (as many math teachers often do), and I took along a set of bathroom scales.  Below is my weight as registered on each planet and the moon.

Planet My Weight (lb.) Weight Factor
Mercury 59.4  
Venus 189.2  
Earth 220 1
Moon 37.4  
Mars 81.4  
Jupiter 580.8  
Saturn 257.4  
Uranus 202.4  
Neptune 316.8  
Pluto 88  

Complete the table by finding the conversion factors to compute weight on each of the planets.

Write a computer, graphing calculator, or spreadsheet program to compute weight on each planet.

Consider the advantages/disadvantages of living on each planet due to the different gravities.


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