PHYS 121 Lecture Notes - Lecture 6: Net Force, Friction
11 Oct 2017
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Objects in motion will continue moving at a constant velocity. Objects do not want to go in circles. Newton"s 1st law: straight lines are natural. If earth disappeared, the moon"s inertia would cause it to go flying off into space. Always directed toward the center of the earth. Measured in newtons (1n = 1kg m/s ) 2. W - magnitude of weight of a body. G - magnitude of acceleration due to gravity. The tension force is always directed towards the pivot. Friction between two surfaces arises from interactions between molecules on the. The object doesn"t want to move due to friction. The kinetic friction force is always the same (for certain materials) Does not depend on the speed or acceleration. The sum of all the forces = 0. A nonzero net force acts on it. Answer: a nonzero net force acts on it. Net force = resultant = vector sum= superposition of force.
