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pumpgirl
Oct 28, 2009, 10:47 AM
How do you find the magnitude of net force.

Nhatkiem
Oct 28, 2009, 11:31 AM
How do you find the magnitude of net force.

usually force is a vector, but the magnitude of a force is just a scalar, so direction isn't something you'll have to worry about, yay!

I will denote with sub n for net

F_n=m_n*a

or if there are multiple forces, then

F_n=\sum_{i=1}^nF_i

This just means it is the magnitudes of each force acting on the object added together (Forces in opposite directions are opposite signs). For example, if we have a free falling object, then the only forces acting on the object are its weight (mg) and drag (usually denoted as F_d, because drag is (up) a force opposite of mg, then the net force is F_d+mg (note that g is a negative value, so you end up subtracting the numbers)

Unknown008
Oct 29, 2009, 08:04 AM
Or if you can draw the forces on a vector diagram, draw the forces to a certain scale you decide and which you'll have to respect. You resolve the forces so that you have them in only two directions, along the horizontal or vertical (if they are forces in free space). Cancel out any force, for example if you have 5 N to the right and 3 to the left, the resultant is 2 N to the right. Then, work out the resultant of the resultant of the two directional forces.