FORCE

FORCE

What is a Force?
1. Force = Push or Pull
  1. When one object pushes or pulls another object, you say that the first object exerts a force on the second object
  2. Newton = The strength of a force is measured in the SI unit
    1. Named after English Scientist, Isaac Newton
  3. Strength and direction of a force can be represented by an arrow
    1. The arrow points in the direction of a force
      1. The longer the arrow, the greater the force
2. A force is described by its strength and by the direction in which it acts
Combining Forces
1. Net Force
  1. Combination of all forces acting on an object
  2. Determines whether an object moves and in which direction it moves
2. Unbalanced Forces
  1. When there is a net force acting on an object, the forces are unbalanced
  2. Unbalanced Forces can cause an object to start moving, stop moving, or change direction
  3. Unbalanced forces acting on an object result in a net force and cause a change in the object's motion
3. Balanced Forces
  1. Equal forces acting on one object in opposite directions
  2. Balanced forces are acting on an object do not change the object's motion
Friction
1. The force that two surfaces exert on each other when they rub against each other
2. Causes of Friction
  1. The strength of the force of friction depends on two factors: how hard the surfaces push together and the types of surfaces involved
  2. In general, smooth surfaces produce less friction than rough surfaces
  3. When the irregularities of one surface come into contact with those of another, friction occurs
3. Static Fricton
  1. Friction that acts on objects that are not moving
  3. Because of static friction, you must use extra force to start the motion of stationary objects
4. Sliding Friction
  1. Occurs when two solid surfaces slide over each other
5. Rolling Friction
  1. When an object rolls across a surface, rolling friction occurs
6. Fluid Friction
  1. Occurs when a solid object moves through a fluid
Gravity
1. Force that pulls objects toward each other
2. Universal Gravitation
  1. Gravity acts everywhere in the universe, not just on Earth
  2. Isaac Newton discovered this
  3. Law of Universal Gravitation
    1. States that the force of gravity acts between all objects in the universe
      1. Any two objects in the universe, without exception, attract each other
3. Factors Affecting Gravity
  1. Two factors affect the gravitational attraction between objects: mass and distance
    1. Mass: a measure of the amount of matter in an object
      1. The more mass an object has, the greater its gravitational pull
        Gravitational force also depends on distance between the objects
4. Weight and Mass
  1. Mass: measure of the amount of matter in an object
  2. Weight: a measure of the amount of matter in an object
    1. The force of gravity on a person or object at the surface of a planet
      1. Weight depends on the strength of gravitational force but mass does not
Gravity and Motion
1. Free Fall
  1. When the only force acting on an object is gravity
    1. In free fall, the force of gravity is an unbalanced force, which causes an object to accelerate
2. Air Resistance
  1. Objects falling through air experience a type of fluid friction called air resistance
  2. Increases w/ velocity
    1. Terminal Velocity: Greatest velocity a falling object reaches
3. Projectile Motion
  1. Projectile: An object that is thrown

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	Criado por babar.m.319 mais de 9 anos atrás