Forces

Forces

1. What is a Force?

   • Combining Forces
     • Balanced Forces
       • Forces have no effect on motion of object
     • Unbalanced Forces
       • Forces affect motion of object
     • Net Force
       • The combination of all forces acting on an object
   • A Push or Pull
     • Described by strength and direction

2. Friction

   • Why does it happen?
     • When two forces rub against each other they create friction
   • Types of Friction
     • Static
       • When an object is not moving
     • Sliding
       • When two suffices slide over each other
     • Rolling
       • When an object rolls across a surface
     • Fluid
       • When a solid moves through a fluid

3. Gravity

   • Universal Gravitation
     • Every object attracts other objects to itself
   • Factors Affecting Gravity
     • Mass and Distance
       • More mass equals more gravitational force
       • More distance between two objects equals less gravitational force
   • Weight and Mass
     • Mass is the amount of matter in an object
     • Weight relies on gravity
   • Motion
     • Free Fall
       • Unbalanced Force
       • When the only force acting on an object is gravity
     • Air Resistance
       • Type of fluid friction that occurs when an object gets slowed down by air
     • Projectile Motion
     • Terminal Velocity

4. Newton's Laws of Motion

   • First Law
     • Inertia
       • Resistance to a change in motion
   • Second Law
     • Determining Acceleration
       • Acceleration = Net Force ÷ Mass
     • Changes in Force and Mass
       • More Net Force = More Acceleration More Mass = Less Acceleration
   • Third Law
     • For Every Action There Is An Equal And Opposite Reaction
     • Action-Reaction Pairs
       • Action-Reaction Forces always occur in pairs

5. Momentum

   • Conservation of Momentum
     • Unless there are outside forces, the total momentum of two interacting objects will not change
   • Momentum = Mass × Velocity

6. Rockets

   • Rockets lift off by expelling gases downward and this force causes an equal and opposite reaction on the rocket

7. Satellites

   • An object that orbits other objects in space
   • Centripetal Force
     • A force that causes an object to move in a circular path
   • Satellites in orbit around Earth are falling but travel around because Earth is curved