Physical Science: Energy and Work

• Physical science involves studying non-living systems; this includes physics, chemistry, geology, and astronomy.
• It explores the fundamental laws and principles governing the universe and matter

Energy

• Energy refers to the capacity to do work.
• Energy exists in various forms, including kinetic, potential, thermal, electrical, chemical, nuclear, and radiant.
• The SI unit of energy is the joule (J).

Work

• Work occurs when a force causes an object's displacement.
• Work is calculated by multiplying the force component in the direction of displacement by the displacement's magnitude.
• To calculate work, use the formula: W = Fd cosθ, where W represents work, F is the force magnitude, d is the displacement magnitude, and θ is the angle between the force and displacement vectors.
• The SI unit for work is the joule (J), which is equivalent to a newton-meter (N⋅m).
• Work is a scalar quantity, possessing magnitude but lacking direction.
• Work can be positive when force and displacement align, negative when they oppose, or zero if there's no displacement or force perpendicular to displacement.

Kinetic Energy

• Kinetic energy is the energy an object has due to its motion.
• Kinetic energy is calculated with the formula: KE = (½)mv², where KE is kinetic energy, m is mass, and v is velocity.
• The SI unit of kinetic energy is the joule (J).
• Kinetic energy is a scalar quantity.

Potential Energy

• Potential energy represents the energy stored in an object based on its position or condition.
• Gravitational potential energy is the energy an object possesses due to its height relative to a reference point, calculated as: PE = mgh, where PE is potential energy, m is mass, g is the acceleration from gravity, and h is the height.
• Elastic potential energy is the energy stored in a deformed elastic object, like a spring, and is calculated as: PE = (½)kx², where PE is potential energy, k is the spring constant, and x is the displacement from the equilibrium position.
• The SI unit of potential energy is the joule (J).
• Potential energy is a scalar quantity.

Conservation of Energy

• The principle of conservation of energy states that energy cannot be created or destroyed, only transformed or transferred.
• In a closed system, the total energy remains constant.
• The total mechanical energy (sum of kinetic and potential energy) in a system is conserved if only conservative forces (e.g., gravity, elastic force) are doing work.

Power

• Power measures the rate at which work is done or energy is transferred.
• Power is the amount of work done or energy transferred per unit of time and is expressed as: P = W/t or P = E/t, where P is power, W is work, E is energy, and t is time.
• The SI unit of power is the watt (W), equivalent to one joule per second (J/s).
• Power is a scalar quantity.
• Power can also be expressed as the product of force and velocity: P = Fv cosθ, where F is the force, v is the velocity, and θ is the angle between the force and velocity vectors.

Equations

• Work: W = Fd cosθ
• Kinetic Energy: KE = (½)mv²
• Gravitational Potential Energy: PE = mgh
• Elastic Potential Energy: PE = (½)kx²
• Power: P = W/t = E/t = Fv cosθ

Math

• Algebra is essential in physical science for equation manipulation and solving unknown variables.
• Trigonometry is used to analyze forces and motion in two dimensions, particularly when dealing with angles.
• Calculus is used in more advanced topics to analyze continuously changing quantities, such as velocity and acceleration.

Explore energy and work in physical science. Learn about forms of energy like kinetic and potential. Understand how work is calculated with force and displacement.