Looking for a Tutor Near You?

Post Learning Requirement » x
Ask a Question
x
x

Direction

x

Ask a Question

x

Hire a Tutor

Presentation On Energy (1)

Published in: Physics
71 Views

This PPT is suitable for the IGCSE and O Level Physics students. It only provides theoretical background of the topic. The practice questions, worksheets and topical questions will be discussed during the tutoring sessions

Tahzeeb I / Dubai

5 years of teaching experience

Qualification: Masters in Telecommunications Engineering

Teaches: Advanced Maths, Basic Computer, Coding & Programming, Mathematics, MATLAB, Physics, Engineering, Chemistry, Computer Science, Maths

Contact this Tutor
  1. Energy (Part 1) Physics (IGCSE / O-Level)
  2. What will you learn in this lesson? • Energy • Energy stores • Energy transfers • Principle of the conservation of energy
  3. Energy Quantity that must be changed or transferred to make something happen Energy can neither be created nor be destroyed but it can only be stored or transferred Energy is explained through model i.e. money Money as a model explaining Energy's We store our money in pockets, ability to be purses and bank accounts. stored When we pay for on item in o shop we ore transferring our Energy con be transferred The unit of energy money from one store (pocket, purse or wallet) to another (the In the United Kingdom, money is measured in pounds sterling (E). HOW links to energy Energy is stored For example, energy is stored in the kinetic energy store in objects that move. Energy con be transferred between different stores. Energy is measured in jpules (J).
  4. Energy Stores Kinetic Energy: A moving object has kinetic energy (k.e.). The faster an object moves, the greater its k.e. Gravitational Potential Energy: If you lift an object upwards, you give it gravitational potential energy (g.p.e.). The higher an object is above the ground, the greater its g.p.e.
  5. Energy Stores (contd.) Identify the k.e. and g.p.e
  6. Energy Stores (contd.) Chemical Energy: Fuels such as coal or petrol/gasoline are stores of chemical energy. We know that a fuel is a store of energy because, when the fuel burns the stored energy is released, usually as heat and light. Nuclear Energy: All radioactive materials (such as Uranium) are also stores of nuclear energy. In these substances, the energy is stored in the nucleus of the atoms — the tiny positively charged core of the atom. Agufe of — Out in
  7. Energy Stores (contd.) Strain (Elastic) Energy Strain energy is the energy stored by an object that has been stretched or squashed in an elastic way. For this reason, it is also known as elastic energy. Internal Energy If you heat an object so that it gets hotter, you are giving energy to its atoms. The energy stored in a hot object is called internal energy. Internal energy is the sum of k.e. and g.p.e. o C)
  8. Energy Stores (contd.) Thermal Energy An object has more energy in its thermal energy store when it is hot than when it is cold. The amount of energy in the thermal energy store depends on the temperature of the object Take care not to confuse the following two forms of energy: Internal energy is the energy of a hot object. Thermal energy (also called heat energy) is the energy spreading out from a hot object. Why steam has more internal energy than boiling water, although they have same temperatures?
  9. Energy Transfers • Mechanical Work A force is applied to move an object, for example when a person lifts a book onto a high shelf or sound-waves from the speakers (which is a way of transferring vibrational kinetic energy) STA R T Ch Store in muscles by doing han iCal END Energy gravi Store Of book
  10. Energy Transfers (contd.) • Electrical Work Charges flow in a circuit, for example in a battery powered toy train. Store
  11. Energy Transfers (contd.) • Thermal Working (Heating) Energy moves from the thermal store of a hotter object to the thermal store of a cooler object, for example when a hand-warmer is used to warm up your hands START thermal in handwarmer Ena•w t ransferred by conduction END Energy in ther store of hands
  12. Energy Transfers (contd.) • Radiation Energy is transferred as a wave, for example light from the bulb, electromagnetic radiation from the sun, and infra red radiation from a toaster to a slice of bread etc. SIART Energy in thermal store of grit' element Enerw transferred by infrar ed radiation ENL) Energy in the rmat store Of food
  13. Energy Stores, Energy Transfers herg kinetic energy (k.e.) gravitational potential energy (g.p.e.) chemical energy elastic (strain) energy nuclear energy internal energy electrostatic energy ergy electrical thermal (heat) radiation (such as light) mechanical (such as sound, which is a way of transferring vibrational kinetic energy)
  14. Energy Stores, Energy Transfers (contd.) Identify the energy stores and energy transfers in the given events and processes
  15. Principle of Conservation of Energy In any energy transfer, the total amount of energy before and after the transfer is constant The above principle shows that energy can neither be created nor be destroyed but it can be stored or transferred The total amount of energy is constant. If we measure or calculate the amount of energy before a conversion, and again afterwards, we will always get the same result. If we find any difference, we must look for places where energy may be entering or escaping unnoticed.
  16. Principle of Conservation of Energy (contd.) A light bulb is supplied with IOOJ of energy each a How many joules ofenergyleave the bulb each second in the form of heat and light? b If IOJ ofenergyleave thelampeach second in the firm of light, how many joules leave each second in the form of heat? A car burns 3 x 105 J of fuel (chemical energy) per second. It has 1.3 x 105 J of kinetic energy and gains 0.7 x 105 J of gravitational potential energy as rt goes up a slope. How muCh energy transfers away from the car through thermal energy transfer? Assume that acceleration due to gravity g = 10 m/s2.