energy transfers

• What is meant by the conservation of energy?

  Energy can be transferred, stored, or dissipated, but cannot be created or destroyed
• What is a system in physics?

  A system is an object or a group of objects
• What is a closed system?

  A closed system is one where no energy can enter or leave
• In the pendulum example, what type of energy is maximum at the top of the swing?

  Gravitational potential energy
• What type of energy is maximum at the bottom of the pendulum swing?


  Kinetic energy
• What happens to kinetic energy as the pendulum swings back up?

  Kinetic energy is transferred to gravitational potential energy
• What is the problem with the pendulum model regarding energy transfer?


  It does not consider friction
• What effect does friction have on the pendulum's energy?

  Friction causes energy to be transferred to thermal energy stores
• What happens to the thermal energy stores due to friction?

  The fixed point and air around the pendulum get warmer
• What do scientists mean when they say energy has been dissipated?


  It has been wasted and is less useful
• What will happen to the pendulum as energy is dissipated?

  It will gradually swing with less energy and eventually stop
• How can unwanted energy transfers in the pendulum be reduced?

  By reducing friction
• What is one method to reduce friction in the pendulum example?

  Using a lubricant such as oil on the fixed point
• What is another method to reduce friction around the pendulum?

  Removing the air particles from around the pendulum
• What does the conservation of energy mean?

  Energy cannot be created or destroyed, only transformed
• How is energy transferred within a system during a bungee jump?

  Energy is transferred from gravitational potential energy to kinetic energy and then to elastic potential energy
• What happens to the energy when the bungee jumper falls?

  Gravitational potential energy is converted to kinetic energy
• What is the maximum point of kinetic energy during a bungee jump?

  When the bungee rope just starts to tighten - at the very bottom
• What happens to kinetic energy when the bungee rope is fully extended?

  Kinetic energy is zero because the jumper is not moving
• What happens to energy when the bungee rope recoils?

  Energy is transferred from the elastic potential energy store back to the kinetic energy store
• What happens to all the energy at the top of the ascent?

  All of the energy is now in the gravitational potential energy store
• Why does the bungee jumper never return to the original position?

  Because energy is dissipated as thermal energy
• What causes energy dissipation during a bungee jump?

  Friction with air particles and stretching effects in the bungee rope
• What type of energy is always dissipated during the bungee jump?

  Thermal energy