Normal Force: Mass on a Surface

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SUMMARY

The discussion centers on the concept of normal force as it relates to a mass resting on a surface. According to Newton's Third Law, the weight of the mass exerts a force on the surface, which in turn applies an equal and opposite force known as the normal force. When the surface is horizontal, the normal force equals the reaction force. However, if the surface is inclined, the normal force is the projection of the reaction force onto the surface normal, resulting in a smaller magnitude than the reaction force itself.

PREREQUISITES
  • Understanding of Newton's Laws of Motion
  • Basic knowledge of force and weight concepts
  • Familiarity with vector projections
  • Knowledge of inclined planes in physics
NEXT STEPS
  • Study the implications of Newton's Third Law in various physical scenarios
  • Explore vector projection techniques in physics
  • Investigate the effects of surface inclination on normal force calculations
  • Review diagrams and examples of normal force from educational resources
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Students of physics, educators teaching mechanics, and anyone interested in understanding the principles of forces acting on objects in static equilibrium.

ShayanJ
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When a mass is on a surface,It applies a force to it because of its weight.According Newton's 3rd law,the surface applies a force to the mass.Can we call this force,Normal force?
 
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In general you would have that the normal force is the projection of the reaction force onto the surface normal.

In your example, if the surface is horizontal, then the reaction force (the force Newtons 3rd law say is opposite the weight in a static situation) is already normal to the surface, so the normal force is in this case the same as the reaction force. If the surface was tilting (but still flat, to keep it simple), then the projection of the reaction force onto the surface normal would give a normal force of smaller magnitude than the reaction force.

See http://en.wikipedia.org/wiki/Normal_force for a few diagrams.
 

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