energy =p1-3

• What does the term "energy" refer to in physics?


  Energy is a number that tells us what will happen when objects interact in a system
• What is the principle of conservation of energy?


  Total energy in any interaction is always conserved; it cannot be created or destroyed
• What is the unit of energy?


  Joules
• How is kinetic energy calculated?


  Kinetic energy is calculated using the formula $e =$$\frac{1}{2} mv^2$
• What does gravitational potential energy depend on?


  Gravitational potential energy depends on mass, gravitational field strength, and height
• What is the formula for gravitational potential energy?


  Gravitational potential energy is calculated using $e =$$mgh$
• What does the specific heat capacity tell us?


  Specific heat capacity tells us how much energy is needed to raise 1 kilogram of a substance by 1°C
• What is the equation for change in thermal energy?


  The equation for change in thermal energy is $e =$$mc\Delta T$
• What happens to particles when thermal energy increases?


  Particles move faster as thermal energy increases
• What is chemical potential energy?


  Chemical potential energy is the energy stored in food or fuels
• What must happen for energy to be transferred in a system?


  Energy must be transferred from one object or store to another
• What is a closed system?


  A closed system is one where no energy is lost or gained from the surroundings
• How can we equate gravitational potential energy and kinetic energy in a roller coaster?


  We can say that gravitational potential energy lost equals kinetic energy gained
• How do you rearrange the kinetic energy equation to find speed?

  Speed is found using $v =$$\sqrt{\frac{2e}{m}}$
• What is the relationship between gravitational potential energy and kinetic energy at the bottom of a fall?

  The gravitational potential energy at the top is converted into kinetic energy at the bottom
• What is work in the context of energy?

  Work is another term for energy used
• How can we find the specific heat capacity of a material practically?

  By heating it and measuring the change in temperature
• What is the equation for power?

  Power is calculated using $P =$$\frac{E}{t}$
• What is the unit for power?

  Watts
• How do you calculate efficiency?


  Efficiency is calculated as useful energy out divided by total energy in
• If a power supply uses 200 watts but only supplies 120 watts of useful power, what is its efficiency?


  The efficiency is 0.6 or 60%
• What happens to heat in poorly insulated buildings?


  Heat can be lost through walls, windows, doors, and roofs
• What are finite energy sources?


  Finite energy sources include fossil fuels like coal, oil, and gas
• What is the difference between energy sources and energy stores?


  Energy sources are where we harness energy from, while energy stores are where energy is kept