part 2

• Density


  Mass ÷ Volume
• Energy Pyramids


  • Shows the amount of energy moving from one feeding level to another
  • Producers are located at the bottom; top-level consumers are located at the top
  • The amount of energy available decreases as you move up the pyramid
• Net Force


  • The overall force exerted on an object
  • Measured in Newtons (N)
  • If the net force is 0, then a change in motion will not occur
  • If the net force is greater than 0, then a change in motion will occur
• Balanced Forces


  • Equal forces that do not cause a change in an object's motion
  • The net force (overall force) on an object must be calculated in order to determine if it is balanced or unbalanced
  • Subtract the forces if the arrows are pointed toward each other or pointed away from each other
  • Add the forces together if the arrows are all pointed the same direction
• Newton's 1st Law


  • The Law of Inertia
  • Inertia – an object's tendency to resist a change in motion
  • An object at rest will remain at rest unless acted upon by an unbalanced force
  • An object in motion will remain in motion with constant velocity unless acted upon by an unbalanced force
• Newton's 1st Law


  • Groceries in a car fly forward when the brakes are suddenly pressed
  • A soccer ball will not move until it is kicked
• Newton's 2nd Law


  • The Law of Acceleration
  • Acceleration – the rate of change of velocity
  • The force of an object is equal to its mass multiplied by its acceleration
  • Force, mass, and acceleration are all related: Force = Mass X Acceleration
• Newton's 2nd Law


  • It requires more force to move a bowling ball than a baseball
  • A small car is able to accelerate faster than a massive truck
• Newton's 3rd Law


  • The Law of Action-Reaction
  • For every action there is an equal and opposite reaction
  • Forces come in pairs when acting on two interacting objects
  • The size of the force on one object is equal to the size of the force on a second object
• Newton's 3rd Law


  • A rocket blasting off
  • A fish is propelled forward by using its fins to push water backward
• Speed


  • The distance an object travels per unit of time
  • Speed = Distance ÷ Time (S = D ÷ T)
  • Average Speed = Total Distance ÷ Total Time
• Speed


  • A person running 10 miles per hour
  • An airplane moving 500 kilometers per hour
• Velocity


  • Speed in a given direction
  • The speed and direction of an object's motion
• Velocity


  • 80 kilometers per hour southwest
  • 100 meters per minute east
  • 10 miles per hour west
• Acceleration


  • The rate of change of velocity
  • Includes an increase in speed, decrease in speed, or change in direction of an object
• Acceleration


  • A car speeds up at a green light
  • A car slows down at a red light
  • A car turns a corner