Ppt Newtons Third Law


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Ppt Newtons Third Law

  1. 1. Newton’s Third Law of Motion
  2. 2. Newton’s Third Law of Motion <ul><li>If you pushed against a wall, what would happen? </li></ul><ul><li>What would happen if you had roller skates on? </li></ul><ul><li>The harder you push? The farther you roll </li></ul>
  3. 3. Newton’s Third Law of Motion <ul><li>Your action caused a reaction. </li></ul><ul><li>Your pushing on the wall caused you to roll backward. </li></ul><ul><li>Newton’s Third Law of Motion states: </li></ul><ul><li>When an object exerts a force on a second object, the second one exerts a force on the first that is equal and opposite in direction. </li></ul><ul><li>AKA – For every action there is an equal and opposite reaction. </li></ul>
  4. 4. Action & Reaction <ul><li>When you apply a force on something a reaction occurs. </li></ul><ul><li>When you jump on a trampoline, you exert a downward force on the trampoline. </li></ul><ul><li>The trampoline then exerts an equal upward force on you, sending you into the air. </li></ul>
  5. 5. Action & Reaction <ul><li>Remember that action-reaction forces are acting on different objects. </li></ul><ul><li>Even though forces are equal, they are not balanced because they act on different objects. </li></ul>
  6. 6. Action & Reaction <ul><li>What is the action and reaction of a swimmer pushing off the wall? </li></ul><ul><li>As the swimmer pushes on the wall, the wall exerts a force pushing her forward. </li></ul><ul><li>As the swimmer pushes the water out of the way, the water pushes the swimmer back. </li></ul>
  7. 7. Action & Reaction <ul><li>What is the action and reaction of the diver? </li></ul>
  8. 8. Rocket Propulsion <ul><li>In a rocket engine, burning fuel makes a hot gas. </li></ul><ul><li>The engine exerts a force on the gases causing the gases to escape outside the back of the rocket. </li></ul><ul><li>The gases exert a force on the rocket and push it forward. </li></ul>
  9. 9. Momentum <ul><li>Which is easier to stop? </li></ul><ul><li>A slow moving bike or a fast moving bike? </li></ul><ul><li>A slow moving bike or a slow moving car? </li></ul>
  10. 10. Momentum <ul><li>Increasing the speed or mass of an object makes it harder to stop. </li></ul><ul><li>Momentum is the product of an objects mass and velocity. </li></ul><ul><li>Momentum is abbreviated with the symbol p . </li></ul><ul><li>p = mv </li></ul><ul><li>Momentum = (mass)(velocity) </li></ul><ul><li>Momentum = kg m/s </li></ul>
  11. 11. The Law of Conservation of Momentum <ul><li>The momentum of an object doesn’t change unless its mass, velocity, or both change. </li></ul><ul><li>Momentum can be transferred from one object to another. </li></ul>
  12. 12. The Law of Conservation of Momentum <ul><li>What happens when a bowling ball hits the pins? If there is no other forces applied… </li></ul><ul><li>The total momentum of the bowling ball is transferred to the pins and the pins go flying. </li></ul><ul><li>The momentum that the pins gained is equal to the total momentum the bowling ball had before it hit the pins. </li></ul><ul><li>Momentum is not lost or created only transferred. </li></ul>