Conservation of Energy

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Conservation of Energy

• Name Nicketa Warner
• Subject Physics
• Class 5E

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Work

• An object which has the ability to do work is
  said to have energy which is measured in
  Joules(J). Work occurs when a force acts upon an
  object displacing it.
• This brings us to the definition of the Joule!
• Named after Prescott Joule(1818- 1889), it is
  defined as the energy transformed or the work
  done when a force of 1 Newton displaces an object
  for a distance of 1m in the direction of the
  force.

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W F x d cos?
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Mechanical Energy

• This is the Energy that objects posses due to
• Its motion(Kinetic Energy)
• Its stored energy( Potential Energy)
• Kinetic Energy
• This is the Energy that an object has due to
  the fact that it is moving. This depend on the
  the mass of the object, and the square of the
  speed of the object.
• This leads us to the formula used.

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In JoulesKinetic energy1/2 x mass x speed2

• BUT WAIT A SECOND! ! !
• Kinetic Energy is different from Potential
  Energy.
• -Potential Energy is the stored energy that an
  object has due to its height above some reference
  point (gravitational potential energy).
• -Energy stored in stretched or compressed elastic
  materials or devices (Elastic Potential Energy)
• -Energy locked up in chemical compounds eg. Bonds
  of gasoline molecules (chemical potential energy)

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Energy Transactions

• Energy is never lost but changes form. The
  process by which energy changes from one form to
  the next is
• known as energy conversion or transferring
  energy. This is related to the principle of
  conservation of energy.
• Ep mgh1- mgh2
• Ep mg(h1 h2)
• Ep mg h
• For Example
• Chemical Energy
  Machanical Energy

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Power

• Power is the rate of conversion of Energy. It is
  the work done or energy converted per unit of
  time.
• Power Force(N) x displacement(m)
• time taken
• Energy transformed
• time taken
• This is measured in Watts (W) or Js-1
• Unfortunately there are some problems
  involving energy transfer

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• Most machines multiply forces, but they do not
  multiply the work done or the energy transferred.
• Friction affects the performance of all machines.
  This means that the efficiency of any machine is
  not 100.
• Less energy or work is got out of machines than
  is put in.
• Energy or
  Energy or
• Work put in.
  Work output
• Wasted Energy
  

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Forms





of Energy

• There are different forms of energy.
• - Chemical Energy
• - Mechanical Energy
• - Thermal Energy
• - Electrical Energy
• - Nuclear Energy

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Some Examples of Energy Conversion Are-

• In the solar electricity industry, solar panels
  convert incident solar radiation to electricity.
• This can then be used to power pumps for
  irrigation and watering stock or recharging
  batteries.
• In every day life we use things such as solar
  water heaters and solar stills.
• With the Solar water heater, water is heated as
  it is pumped through blackened copper pipes into
  what is called an absorbing panel. The heat is
  then transferred to the hot water tank by a coil.

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Energy conversion and the caribbean

• In the Caribbean a significant proportion of the
  energy used is derived from oil and natural gas.
• Were talking more than 40!
• Because of this some countries of the region for
  example Trinidad and Tobago will have high energy
  import bills.
• To try to rectify this problem it will be best if
  more renewable sources of energy for example,
  solar energy are used

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Renewable and Non-Renewable

• Renewable
• -Solar Power
• -Biomass
• -Wind Power
• -Hydropower
• -Geothermal

• Non- Renewable
• -Oil
• -Natural Gas
• - Coal

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• To the left is a pie chart showing the use of the
  different types of energy.
• Here in the caribbean, in order to cut down on
  the use of non-renewable energy resources we must
  increase the use of renewable sources eg. Biofuel
  and ethanol.
• Solar, geothermal and wind.

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Energy Use in the Caribbean

• One of the Renewable sources of Energy in the
  caribbean that has a lot of benefits is Solar
  Energy.
• --- With Air conditioning a shift to solar power
  can lead to a big reduction in running costs.
• --- There can be an increase in hot water systems
  in homes, hotels etc.
• Also in the areas with the young volcanoes can
  get benefits with using geothermal energy.
• --- This can be used to heat greenhouses, to dry
  fish etc.