Monday, February 2, 2009

An Example of Vector Physics

Assume you try to pull a box across the room. You exert 150 pounds of pressure (which you could measure with a spring) on the box, how much force will be used to drag the box and how much to lift it? This problem can be solved with trigonometry.

Sketch of how trigonometry and vector physics can measure force

Thus from the sketch we see we can calculate horizontal force as
150 * cos(40) = 115 lbs of force
We get this equation knowing that the cosine of an angle is adjacent over hypotenuse, thus
adjacent = hypotenuse*cosine(angle)
115 = 150 * cos(40)

By the same method we can find the opposite side which will give us the force of lift.
150 * sin(40) = 96 pounds

Whether or not this is enough force to move the box depends on the friction and weight of the box, as well as several other variables.

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