Newton's Law

• What is inertia?

  Resistance to change in motion
• Example of inertia?

  Card is on glass and has a coin on it. If card is pulled quickly the coin will stay in the same place - it won't move with the card. It will then fall into the cup.
• More mass means more inertia. A greater resultant force would be needed to change the motion on a object with high inertia
• What is Newton's first law?

  A body will continue in its state of rest, in a straight line unless a resultant force acts upon it
• What does Newton's second law state?

  An object's acceleration is directly proportional to the resultant force acting on it and inversely proportional to its mass
• This car decelerates. It is moving to the opposite direction of the resultant force

  Acceleration and mass are inversely proportional. Mass of vehicle doubles, acceleration half's if resultant force stays the same

  Resultant force and acceleration are directly proportional. If the resultant force doubles, the acceleration of the vehicles also doubles if the mass of the vehicle stays the same

  
• Objects moving in water or air

  When objects move faster in water (air), drag forces increase. As the drag force is increased, resultant force decreases. When the drag force becomes the same weight of the weight, the forces become balanced. No resultant force and the object stops accelerating. Continues to move at constant speed. Constant speed is called terminal velocity
• How is drag force created?

  Moving through air causes collisions with air molecules. Friction between moving bodies and particles, causes some of the kinetic energy to be converted into heat. Air molecules bounce of the object gaining kinetic energy.

  Faster a object moves - more collisions with air molecules. Increases friction and they gain more kinetic energy
• What is Newton's third law?

  Whenever two objects interact, the forces they exert on each other are equal and opposite
• What is resultant force?

  The sum of all the individual forces acting on a object (taking directions into account)
• What is inertial mass?

  • A measure of how difficult it is to change a given object's velocity
  • The ratio of force over acceleration
• What is the unit used for weight?

  The newton N
• What happens to a magnitude of air resistance on a falling object when the velocity increases?

  As velocity increases, the force of air resistance on the object will also increase