(ANL) Module Overview - Application of Newton's Laws

Application of Newton's Laws

Application of Newton's Laws

Introduction

The ancients believed that objects naturally returned to their natural state, or to the place they were supposed to be. That is, things made mostly of Earth came back to the Earth, and those things made mostly of air could fly or float. We now know that forces are required to cause an object to speed up or slow down. It makes sense to us that objects accelerate when dropped because of their weight (the force of gravity) and they stop when moving due to friction. But what about objects at rest? Do forces act on a ball in the grass? What about a sign hanging from a pole? How does an object stay in a circular pathway? In this module we will apply Newton's Laws of Motion to solve for the forces in different situations. 

Module Lessons Preview

In this module, we will study the following topics:

  • What are the forces acting on a moving or stationary body, including friction, weight, and the normal?
  • How can the tension on static and accelerated objects be calculated?
  • How can we determine the forces between objects in a system?
  • What is the force that causes an object to accelerate down a slope?
  • What is the relationship between friction and the normal force?
  • What is the centripetal force and how does it cause an object to move in a circular pathway?
  • What field force exists between all objects with a mass?

 

Key Terms

  1. Attwood Machine: A system designed to study forces that consist of two masses connected by a massless inextensible string over a frictionless pulley.

  2. Centripetal Acceleration: The acceleration of any object that is in a circular pathway, directed perpendicular to the path of the object causing it to change direction so as to stay in that circular path.

  3. Centripetal Force: The force directed toward the center of a curved pathway that causes the object to accelerate so as to stay in the curved pathway.

  4. Friction: A force that opposes the motion between two objects that are in contact and moving and are attempting to move past each other.

  5. Newton's Law of Universal Gravitation: The force between any two masses is directly proportional to the masses and inversely proportional to the square of the distance between their centers of mass.

  6. Normal Force: The force perpendicular to the surface on any object in contact with a surface.

  7. Parallel Component of Weight: The component of the weight of an object on an incline that points parallel to the slope (mgsinθ).

  8. Perpendicular Component of Weight: The component of the weight of an object on an incline that points perpendicular to the slope (mgcosθ).

  9. Tension: The force due to the pull of a string or rope on an object.

  10. Weight: The force on an object due to the pull of the Earth. It is always directed down (toward the center of the Earth) and has a value of W=mg, where m is the mass in kilograms, g is the acceleration due to gravity, and W is the weight in Newtons.

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