We are now going to study how forces work by using a jet powered airplane as an example.
Newton's second law of motion gives a definition of force:
which scientists would abbreviate by the equation: F = m a
People often confuse the mass of an object with the weight of the object. The weight is a measure of the gravitational force on the object. It is equal to the mass times the gravitational acceleration. Scientists would express this as:
where W is the weight and "g" is the gravitational acceleration (gravity).
On the surface of the earth "g" is equal to 32.2 ft per second squared in English units or 9.81 meters per second squared in Metric units. The value of "g" decreases very slowly as you move away from the surface of the earth. But, in the atmosphere, below 50,000 ft, we can assume that the value does not change.
Weight is a force that depends on the mass of an object. The mass of an object depends on how many and what kinds of atoms (carbon, lead, iron, etc...) the object is made from. If we measure the weight on a scale, we can determine the mass by using the weight equation given above.
Let's determine the mass of different aircraft by finding the weight on the Engine Control Panel. Calculate the mass using the weight equation. You can either enter your answer into the white display box labeled "Mass" or you can choose a "Multiple Choice" answer. When you think you have the correct answer, push the "SUBMIT ANSWER" button.
Push the "New Problem" button to get a new set of conditions to work on. You can also change the type of aircraft for these problems.
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