Gravity, Friction, Energy, Sources

• Acceleration


  A change of velocity when something speeds up, slows down , or changes direction.
• Weight


  The force of gravity pulling on mass.
• Force


  A push or pull
• Projectile


  Any object that moves freely while being pulled down by gravity.
• Trajectory


  The path an that a projectile takes.
• Free Fall


  Any object that falls in a straight line down.
• Friction


  The force that opposes motion.
• Fluid Friction


  The resistant force of a gas or liquid as something moves through it.
• Fluid


  Any substance that can flow on it's own. (Liquid or Gas)
• Force Scale


  The instrument that measures how much force is present such as weight.
• Orbit


  The path one object takes around another usually much bigger object like the earth traveling around the sun.
• Air resistance


  The resistant force of a gas as something moves through it.
• Weight =


  Mass x Gravity
• 9.8 m/s/s


  The acceleration of gravity on Earth.
• Sliding Friction


  The resistant force against moving when a solid slides across another solid.
• Rolling Friction


  The resistant force of an object rolling across another object.
• Parabola


  The reverse u-shaped curve trajectories look like.
• elliptical


  An oval shape; Not a perfect circle
• force


  a push or pull on an object
• contact force


  a push or pull on one object by another that is touching it
• noncontact force


  a force that one object can apply to another object without touching it
• gravity


  is an attractive force that exists between all objects that have mass
• mass


  is the amount of matter in an object
• weight


  is the gravitational force exerted on an object
• friction


  is a force that resists the motion of two surface that are touching
• net force


  the combination of all the forces acting on an object
• balanced force


  forces acting on an object that combine and form a net of zero
• Newton's first law of motion


  if the net force on an object is zero, the motion of the object does not change
• Newton's second law of motion

  the acceleration of an object is equal to the net force acting on the object divided by the objects mass
• circular motion


  is any motion in which an object is moving along a curved path
• centripetal force


  in circular motion, a force that acts perpendicular to the direction of motion, toward the center of the curve
• Newton's third law of motion

  when one object exerts a force on a second object, the second object exerts and equal force in the opposite direction on the first object
• force pair


  is the force two object apply to each other;
• action force


  when you push against an object
• reaction force


  the object pushes back
• momentum


  is a measure of how hard it is to stop an object
• momentum equation


  mass times velocity
• Law of conservation of momentum


  the total momentum of a group of objects stays the same unless outside forces act on the objects
• Friction


  A force that opposes motion between two surfaces that are in contact
• rolling friction


  friction that occurs when an object rolls over a surface