- Energy is the ability to do work.
- Work is done when a force moves an object over a distance.
- Force is a push or pull on an object.
- The unit of energy and work is the joule (J).
- The formula for work is: Work = Force × Distance.
- If no distance is moved, no work is done, even if force is applied.
- A machine can make work easier by changing the size or direction of a force.
- Mechanical advantage is the ratio of output force to input force.
- Efficiency is the ratio of useful work output to total work input, expressed as a percentage.
- Energy cannot be created or destroyed, only transformed or transferred (Law of Conservation of Energy).
- Potential energy is stored energy due to position or condition.
- Kinetic energy is energy of motion.
- Gravitational potential energy depends on mass, gravity, and height.
- Kinetic energy depends on mass and velocity squared.
- Friction converts mechanical energy into thermal energy.
- Power is the rate at which work is done or energy is transferred.
- The unit of power is the watt (W), equal to one joule per second.
- Simple machines include levers, pulleys, inclined planes, wedges, screws, and wheel and axles.
- A lever has a fulcrum, effort arm, and load arm.
- A pulley changes the direction of force or multiplies force depending on setup.
- An inclined plane reduces the force needed by increasing the distance over which it is applied.
- Energy transformations occur in everyday devices like light bulbs, engines, and batteries.
- Renewable energy sources include solar, wind, hydro, and geothermal.
- Nonrenewable energy sources include coal, oil, natural gas, and nuclear.
- Fossil fuels are formed from ancient organic matter and are finite.
- Energy efficiency means using less energy to perform the same task.
- Insulation reduces heat transfer and improves energy efficiency in buildings.
- Calculating work requires knowing both force and distance in the direction of the force.
- Calculating power requires knowing work done and time taken.
- Mechanical advantage greater than 1 means the machine multiplies force.
- Efficiency less than 100% means some energy is lost, usually as heat.
- Understanding energy and work helps design better machines and conserve resources.
Parent Tip: Review the logic above to help your child master the concept of work energy and power worksheet answer key.
