Gibson, Everett » Unit 3: Force and Motion Overview

Unit 3: Force and Motion Overview

(8.6A) Students will demonstrate and calculate how unbalanced forces change the speed or direction of an object’s motion.
 
  • Force - A push or pull on an object
  • Newton - The standard unit of measurement for Force
  • Net Force - The combination of all the forces acting on an object
  • Balanced Forces - Forces that cancel one another and allow an object to maintain its motion 
  • Unbalanced Forces - Forces that do not cancel one another and cause an object's motion to change  
  • Normal Force - The force that a surface exerts on an object that is pressing on it 
  • Friction - The force that opposes motion between two objects that are touching
  • Gravity - The attractive force between anything two things that have mass 
  • Applied Force - Forces that involve direct contact 
(8.6B) Students will differentiate between speed, velocity, and acceleration.
 
  • Speed - The measure of how quickly distance changes with time
  • Velocity - The speed of an object in a particular direction
  • Acceleration - A Change in speed, direction, or both. (Starting, stopping, speeding up, slowing down, and or changing direction)
(8.6C) Students will investigate and describe applications of Newton’s three laws of motion such as in vehicle restraints, sports activities, amusement park rides, Earth’s tectonic activities, and rocket launches.
 
  • Newton's 1st Law of Motion - An object at rest remains at rest, or if in motion, remains in motion at a constant velocity unless acted on by a net external force. 
  • Inertia - The tendency of an object to resist a change in motion 
  • Newton's 2nd Law of Motion - The acceleration of an object is dependent upon two variables - the net force acting upon the object and the mass of the object. The acceleration of an object depends directly upon the net force acting upon the object, and inversely upon the mass of the object. As the force acting upon an object is increased, the acceleration of the object is increased. As the mass of an object is increased, the acceleration of the object is decreased.
    • Force = mass X acceleration (F = ma)
    • acceleration = Force / mass (a = F/m)
    • mass = Force / acceleration (m = F/a)
  • Newton's 3rd Law of Motion - For every action, there is an equal and opposite reaction.