Weekly Agenda (4/14 - 4/18)

Weekly Agenda (4/7 - 4/11)

Energy Flow Practice 2

    1. Hybrid Car System
      A hybrid car engine receives 9,000 J of chemical energy from fuel and 2,000 J of electrical energy from a battery. The car uses 5,000 J for motion, loses 3,000 J as heat from the engine, and 2,000 J is lost in friction and air resistance.
      Task: Identify and label all energy inputs, useful outputs, and wasted outputs in a diagram.


    1. Industrial Heat Pump
      A heat pump transfers 1,500 J of heat from a cold warehouse to a warmer outside environment. It uses 500 J of electrical energy to operate. During the process, 200 J is lost due to inefficiencies.
      Task: Create a diagram that includes energy input from electricity, heat moved, and heat lost. Then, calculate how much total heat is released outside.


    1. Human Body in Exercise
      A person consumes a high-energy drink with 3,000 J of energy. During a workout, they use 1,500 J for muscle work, 1,000 J is lost as heat, and the rest is stored as chemical energy in muscle tissue.
      Task: Draw an energy flow diagram showing all transfers and calculate how much energy is stored.


    1. Battery Charging and Usage
      A battery receives 2,500 J of electrical energy during charging. 2,000 J is stored, while 500 J is lost as heat. Later, when powering a motor, 1,500 J of the stored energy is used, producing 1,000 J of work and 500 J of heat.
      Task: Draw two energy diagrams: one for charging and one for usage. Identify all energy paths and total energy conserved or lost in each stage.


    1. Steam Turbine System
      A power plant burns fuel to provide 15,000 J of heat to a boiler. The steam generated does 6,000 J of work spinning a turbine. 4,000 J is lost as heat through the exhaust, and 3,000 J is transferred to the cooling system.
      Task: Draw an energy flow diagram showing how energy moves through the system and calculate how much energy remains unaccounted for (if any).

Weekly Agenda: (3/24-3/28)

Energy Flow Diagrams

  • Basic Energy Flow Calculations:

    1. A system absorbs 500 J of heat and does 200 J of work on the surroundings. What is the change in internal energy? Draw an energy flow diagram.

    2. A gas is compressed, and 300 J of work is done on it while it loses 100 J of heat to the surroundings. Calculate the net change in internal energy and illustrate the energy transfers.

    3. A steam engine receives 1,200 J of heat from burning fuel and does 800 J of work. How much energy is lost to the surroundings? Represent this in an energy flow diagram.

    4. A gas expands, doing 250 J of work while absorbing 400 J of heat. What is the internal energy change? Show how the energy is distributed in a diagram.

    5. A refrigerator removes 600 J of heat from inside and expels 750 J to the surroundings. How much work does it require to operate? Create a diagram to explain.

    More Complex Energy Flow Calculations (Multiple Inputs & Outputs):

    1. A battery-powered motor receives 1,500 J of electrical energy. It converts 800 J into mechanical work, loses 500 J as heat, and stores the rest. How much energy remains stored in the system? Draw an energy flow diagram.

    2. A car engine takes in 10,000 J of chemical energy. It converts 3,500 J into useful work, loses 4,000 J as exhaust heat, and transfers the rest as heat to the engine block. How much heat is absorbed by the engine block? Represent this in a diagram.

    3. A solar panel absorbs 2,000 J of sunlight. It converts 900 J into electrical energy, loses 600 J as heat to the environment, and reflects 500 J of sunlight. Illustrate the energy flow.

    4. A compressed gas system receives 700 J of heat and 400 J of work. It loses 300 J as heat to the surroundings while doing 500 J of work. What is the net change in internal energy? Draw an energy flow diagram.

    5. A human body metabolizes 2,500 J of food energy. 1,200 J is lost as heat, 800 J is used for movement, and 300 J is stored as fat. Show the energy flow in a diagram.

Weekly Agenda (3/17 - 3/21)