The forces and movement

The forces and movement

1. Forces and balance

   • A force is a push or pull upon an object resulting from the object's interaction with another object. Whenever there is an interaction between two objects, there is a force upon each of the objects. Forces only exist as a result of an interaction.
   • Newton
     • Its units are Newtons (N)
   • Force as a vector
     • Force module
       • Numerical value of the strength of the force
     • Force direction
       • Line that contains the value of the force
     • Force sense
       • Indicated by the arrow of the vector
   • Composition of forces and balance
     • Resultant force
       • This is a single force that has the same effect on the object as all the individual forces acting together.
     • Balanced forces

2. Effects of forces

   • Alterations of the state of movement
     • Newton's first law. Law of inertia
       • An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
     • Newton's second law.
       • The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.
         • F = m*a
       • Newton's third law.
         • For every action, there is an equal and opposite reaction.

3. If the net force is zero, the acceleration is zero, and the velocity does not change, it is constant; therefore, the movement can be: Uniform rectilinear movement (MRU) or it can be an object at rest.

   • F=0

4. If the net force is not zero, the mobile has acceleration (or deceleration); therefore, the movement is uniformly varied or Uniformly accelerated or uniformly retarded.

   • F ! = 0