Energy changes in a system

• What is defined as a system in physics?

  An object or group of objects
• Why is defining a system important in physics?

  It narrows parameters to focus on relevance
• What happens when a system is in equilibrium?

  Nothing changes and nothing happens
• What occurs when there is a change in a system?

  Energy is transferred
• What happens to an apple when the table is removed?

  The apple will fall

  
• How is energy measured?

  In units of joules (J)
• What types of thermodynamic systems exist?

  Isolated, closed, or open

  
• What is an open system?

  Allows exchange of energy and matter

  
• What is a closed system?

  Can exchange energy but not matter

  
• What is an isolated system?

  Does not allow transfer of matter or energy

  
• What happens to energy when a change occurs in a system?

  Energy is transferred between objects or stores
• What does the principle of conservation of energy state?

  • Energy cannot be created or destroyed
  • It can only be transferred between stores
  • Total energy in a closed system is constant
• What is kinetic energy?

  Energy of moving objects
• How does gravitational potential energy change when an object is lifted?

  Energy is transferred to its gravitational potential store
• What happens to gravitational potential energy when an object falls?

  Energy is transferred away from its gravitational potential store
• What is the equation for kinetic energy?

  E = ½ × m × v²
• How do you calculate kinetic energy for a mass of 1200 kg moving at 27 m/s?

  E = 437,400 J
• What is gravitational potential energy defined as?

  Energy due to an object's height in a gravitational field
• What is the equation for gravitational potential energy?

  E = m × g × h
• What is the approximate gravitational field strength on Earth?

  9.8 N/kg
• How much energy is transferred to a man's gravitational potential energy store when he climbs 3 m?

  2,058 J
• What happens to gravitational field strength on the Moon compared to Earth?

  It is less on the Moon
• What happens to gravitational field strength on gas giants compared to Earth?

  It is greater on gas giants
• How does energy transfer occur when a vehicle accelerates?

  Energy is transferred to the kinetic store
• What happens to energy when a vehicle slows down?

  Energy is transferred to the thermal store
• How is energy transferred when boiling water in a kettle?

  By electrical working to the thermal store
• What is the effect of friction when a vehicle slows down?

  It transfers energy to the thermal store
• What is the role of sound waves in energy transfer?

  They transfer energy away from the system
• What happens to energy when an object is projected upwards?

  Energy is transferred to the kinetic store
• How does energy transfer occur when a moving object hits an obstacle?

  Energy is transferred to the thermal store
• What happens to energy when a vehicle speeds up?

  Energy is transferred to the kinetic store
• What is the energy transfer when water is boiled in an electric kettle?

  Electrical energy to thermal energy
• What is the significance of defining the system in energy transfer problems?

  It helps keep answers concise and focused
• What is the relationship between mass and gravitational potential energy?

  More mass means more gravitational potential energy
• How does height affect gravitational potential energy?

  Higher objects have more gravitational potential energy
• What is the effect of gravitational field strength on energy calculations?

  Higher gravitational field strength increases energy
• What is the energy transfer when a ball is thrown upwards?

  From chemical store to kinetic store
• What happens to energy when a car hits a wall?

  Energy is transferred to the thermal store
• What is the energy transfer when a vehicle decelerates?

  Energy is transferred to the thermal store
• What is the energy transfer when a hot coffee warms cold hands?

  Energy is transferred by heating