Energy Transfers

• mechanical transfers in energy are when energy is transferred by physical contact, such as pushing or pulling.
• What is the energy transfer when a ball rolls us a slope?

  Energy is transferred mechanically from the kinetic energy of the ball rolling to gravitational as the ball is gaining as it moves further up the hill.
• Dissipation is often used to describe ways in which energy is wasted in a system.
• A rise in temperature is caused by the transfer of wasteful energy in mechanical processes. The energy is dissipated in the system . In a mechanical system, energy is dissipated when two surfaces rub together (friction).
• Electrical cables warming up is an example of dissipation as it is not useful to have hot wires behind a television as energy is dissipated to the surrounding air.
• What is the energy transfer of a bat hitting a ball?

  the bat has energy it it's kinetic store. Some of this is transferred to the balls kinetic store(causing the ball to move). However some is also transferred as thermal as they hit each other and is wasted in the surrounding air.
• What is the energy transfer from a rock getting dropped from a cliff?

  As the rock falls the rock's gravitational potential energy (gained from getting higher in the air) is transferred into its kinetic store(speed increasing till it hits the ground)
• what is the energy transfer from a car slowing down?

  The energy store of the car is transferred mechanically to the thermal energy store of the road(due to friction between the tyres and road)
• what is the energy transfer that happen when a kettle boils water?

  Energy is transferred electrically from the power source to the kettle and by heating transferred to the thermal store of the water.