1.1.3 Describing Energy Changes in a System

• What are energy stores?

  Forms of stored energy
• Kinetic energy is the energy of movement
• Gravitational potential energy depends on height in a gravitational field.
• Where is elastic potential energy stored?

  Stretched or compressed objects
• Chemical energy is stored in chemical bonds
• Match the energy store with its description:

  Nuclear Energy ↔️ Energy within the nucleus of atoms

  Thermal Energy ↔️ Energy of heat within an object

  Magnetic Energy ↔️ Energy stored in magnetic fields

  Electrostatic Energy ↔️ Energy stored in electric fields
• What is an energy system?

  Stores and transfers energy
• An example of kinetic energy is a rolling ball
• Where is nuclear energy commonly used?

  Nuclear power plants
• Conduction involves the movement of fluids to transfer energy.

  False
• Convection transfers energy through the movement of liquids and gases
• How does radiation transfer energy?

  Electromagnetic waves
• Mechanical work involves forces acting over a distance to transfer energy.
• Arrange the modes of energy transfer in order from most to least efficient:

  1️⃣ Conduction

  2️⃣ Convection

  3️⃣ Radiation
• What is conduction in the context of energy transfer?

  Thermal energy through contact
• Convection is the transfer of thermal energy through the movement of fluids
• Radiation is the transfer of energy through electromagnetic waves.
• What is an example of mechanical work in energy transfer?

  Pushing a box
• Work done is calculated using the formula W = F × d cos(θ)
• The angle θ in the work done formula represents the angle between the force and the direction of motion.
• What is the work done if a force of 50 N moves an object 2 meters horizontally in the same direction as the force?

  100 J
• Power is the rate at which work is done or energy is transferred
• What is the formula for calculating power using work done and time taken?

  $P =$$\frac{W}{t}$
• High power output indicates rapid energy consumption.
• Energy stores are the various forms in which energy is stored
• Match the energy store with its example:

  Kinetic energy ↔️ A moving car

  Gravitational potential energy ↔️ A book on a shelf

  Elastic potential energy ↔️ A compressed spring

  Chemical energy ↔️ Food or fuel

  Nuclear energy ↔️ Nuclear power plants

  Thermal energy ↔️ Hot water
• What is an example of magnetic energy?

  Refrigerator magnet
• Energy transfers between stores always involve the conversion of energy from one form to another.
• What is the primary method of energy transfer in sunlight warming the Earth?

  Radiation
• Energy transfers between stores always involve converting energy from one form to another.
• Match the mode of energy transfer with its description:

  Conduction ↔️ Transfer of thermal energy through direct contact

  Convection ↔️ Transfer of thermal energy through fluid movement

  Radiation ↔️ Transfer of energy through electromagnetic waves

  Mechanical Work ↔️ Transfer of energy by forces acting over a distance
• Conduction is the transfer of thermal energy through direct contact
• What type of energy transfer occurs when warm air rises in a room?

  Convection
• Mechanical work involves energy transfer by forces acting over a distance.
• What is an example of electrical work?

  Charging a phone battery
• In a battery-powered device, chemical energy is converted to electrical energy through electrical work
• Steps involved in calculating work done

  1️⃣ Identify the force applied

  2️⃣ Determine the distance moved

  3️⃣ Measure the angle between force and motion

  4️⃣ Calculate work done using the formula
• What is the formula for calculating work done?

  $W =$$F \times d \cos(\theta)$
• In the formula for work done, \( W \) represents work done in joules
• What is the unit of force in the work done formula?

  Newtons