Physics Work and Energy Concepts

Work

• Definition: Work is the transfer of energy that occurs when a force is applied to an object and causes displacement.
• Formula: Work (W) = Force (F) × Displacement (d) × cos(θ)
  • θ = angle between the force and displacement direction.
• Units: Joules (J) where 1 J = 1 N·m (Newton-meter).
• Conditions:
  • Work is done only when there is displacement.
  • No work is done if the force is perpendicular to the displacement (cos(90°) = 0).

Energy

• Definition: Energy is the capacity to do work.
• Types of Energy:
  • Kinetic Energy (KE): Energy of an object in motion.
    • Formula: KE = (1/2) mv², where m = mass, v = velocity.
  • Potential Energy (PE): Energy stored in an object due to its position or configuration.
    • Gravitational Potential Energy: PE = mgh, where h = height above a reference point.
• Law of Conservation of Energy: Energy cannot be created or destroyed, only transformed from one form to another.

Power

• Definition: Power is the rate at which work is done or energy is transferred.
• Formula: Power (P) = Work (W) / Time (t)
• Units: Watts (W) where 1 W = 1 J/s (Joule per second).
• Alternative Formula: P = F × v, where F = force and v = velocity.
• Importance: Power indicates how quickly work can be done; higher power means more work done in less time.

Work

• Work involves energy transfer through force leading to displacement of an object.
• Formula for calculating work: Work (W) = Force (F) × Displacement (d) × cos(θ), where θ is the angle between the force and displacement.
• Measured in Joules (J), with 1 Joule equivalent to 1 Newton-meter (N·m).
• Work requires actual displacement; no work is done if displacement is zero or if the force is applied perpendicular to the direction of displacement (cos(90°) = 0).

Energy

• Energy defines the ability to perform work.
• Kinetic Energy (KE): The energy possessed by an object due to its motion, calculated using KE = (1/2) mv² (m = mass, v = velocity).
• Potential Energy (PE): Energy stored based on an object's position or state, prominently gravitational potential energy, represented by PE = mgh (m = mass, g = gravitational acceleration, h = height).
• The Law of Conservation of Energy asserts that energy cannot be created or destroyed; it can only change forms.

Power

• Power quantifies the speed at which work is accomplished or energy is transferred.
• Power is calculated with the formula: Power (P) = Work (W) / Time (t).
• Expressed in Watts (W), where 1 Watt equals 1 Joule per second (J/s).
• An alternative format of power calculation: P = F × v, where F represents force and v represents velocity.
• Higher power indicates a greater capability to perform work in a shorter amount of time.