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Physics/Normal Force



When I stand still on the floor, I exert , through gravity a force of Mg on the floor and the reaction is the floor exerting an equal and opposite force of Mg on me. Is this the Normal Force?

On an incline the Normal Force is perpendicular to the incline surface and the gravitational force is vertically downwards...if I vectorialy add the Normal Force and the Mg..what do I get? Can this be the resistive force that keeps the block from slipping?


Yes it is, and yes you have it correct.  The component of the normal force along the plane that keeps the block from slipping is the force that keeps it from slipping.  You have to break the normal force (an unknown in that problem, it is a response force which is as large as it needs to be to satisfy the physics of static non-acceleration) into components, as well.


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Dr. Stephen O. Nelson


I can answer most basic physics questions, physics questions about science fiction and everyday observations of physics, etc. I'm also usually good for science fair advice (I'm the regional science fair director). I do not answer homework problems. I will occasionally point out where a homework solution went wrong, though. I'm usually good at explaining odd observations that seem counterintuitive, energy science, nuclear physics, nuclear astrophysics, and alternative theories of physics are my specialties.


I was a physics professor at the University of Texas of the Permian Basin, research in nuclear technology and nuclear astrophysics. My travelling science show saw over 20,000 students of all ages. I taught physics, nuclear chemistry, radiation safety, vacuum technology, and answer tons of questions as I tour schools encouraging students to consider careers in science. I moved on to a non-academic job with more research just recently.

Ph. D. from Duke University in physics, research in nuclear astrophysics reactions, gamma-ray astronomy technology, and advanced nuclear reactors.

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