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