Sunday, February 24, 2013

Conservation of Mechanical Energy

Mechanical Energy
The energy that is associated with motion is known as mechanical energy. There are two forms of mechanical energy, otherwise known as kinetic and potential energy.

Examples:

  • A flying aircraft
  • A moving vehicle

Kinetic Energy
Kinetic Energy occurs when the object is in motion.

Examples:

  • A moving bicycle














Potential Energy
Potential Energy occurs when the object is not in communication with the ground. 

Examples:

  • A flying kite
  • A hanging swing













Formulas

  • Kinetic Energy
    • 1/2 x V2
  • Potential Energy
    • m x g x h


Conservation of Energy
Energy that can't be made or destroyed but can only be transformed is known as conservation of energy. 

Sunday, February 17, 2013

More About Sources of Energy





  • Fossil fuels are considered as a source of energy which is not renewable. Why is it so?

    • The reason why fossil fuels are considered as nonrenewable energy is because it takes thousands of years to be produced.

  • What happens if the fuel consumption is not spared?

    • If  fuel is not spared between regions, the prices will increase in the areas that don’t posses as much fuel.
  • Write down the dangerous issues of having a nuclear power plant.
    • Nuclear power plants are extremely dangerous. They can easily leak at any point in time. For instance, in the year 2011, Fukushima Daiichi, Japan was faced against a tsunami, which caused a nuclear power plant to leak radioactive waste into the sea.

  • According to your opinion, in order to produce electrical energy, what is the best energy that fits with the current situation and is pollution free?

    • In my opinion, I think that using solar panels is the best method in order to create electrical energy. This system is entirely pollution free and can be very helpful in areas of long sun hours such as Jakarta.


  • Write your suggestions in order to produce a very high temperature, so that a large amount of electricity can be generated from the use of seawater.
    • Fusion energy can be used to help generate electricity from the use of seawater.

Sunday, February 10, 2013

Sources of Energy


Sources of energy can be composed of food, sunrays, and waterfalls.

There are two types of sources of energy: the first being renewable energy and the second nonrenewable.

Renewable Energy:
·      Wind Energy
o   Windmills are used to generate electricity for the many purposes needed. However, the amount of energy produced is relatively small and size of a windmill is quite large.

·      Waterfall Energy
o   Using turbines is another way to produce energy. Water is used to rotate the turbine henceforth creating energy.

·      Solar Energy
o   With the help of solar panels, it is now possible to create solar energy. Solar panels are usually placed on the roof of a house to collect solar energy from the sun.

·      Nuclear Energy
o   The splitting of an atomic nucleus is known as fission. This process can generate a powerful source of energy.

·      Tidal Energy
o   Tidal power from rivers is used to generate another source of energy.

·      Geothermal Energy
o   The steam that comes from a geyser can be of help when producing energy.

·      Biomass Energy
o   The energy that comes from plants or animals is called biomass energy. Alcohol can be made from plants, which then can be used for fuel.

Nonrenewable Energy:
·      Fossil Fuel
o   Examples: Charcoal, gasoline

Sunday, February 3, 2013

Work Assignment


A tugboat pulls a ship with a constant force of 5000 N, causing the ship to move through a harbor. How much work does the tugboat do on the ship if each moves a distance of 3 km?

Answer:
W= F x D
= 5000 N x 3000 m
= 15 000 000 J
= 15 MJ

A husky dog does 20 kJ of work as he pulls a sleigh with a force of 340 N. Through what distance does he pull it?

Answer:
W= F x D
W = 20 000 = 340 x D
D = 20.000/ 340
= 58.8 m

What is the weight of a mass of 100 kg? Find the work done in raising a mass of 100 kg through a vertical height of 60 m.

Answer:
W = F x D
= 1000 x 60
= 60 000 J
= 60 KJ

Carlos does a chin-up in gym class and raises himself 0.8 m. If Carlos has a mass of 62 kg, how much work does he accomplish?

Answer:
W = F x D
= 620 x 0.8
= 490 J

A girl pushes her little brother on his sled with a force of 300 N for 750. m. How much work is this if the force of friction acting on the sled is (a) 200 N, (b) 300 N?

Answer:
a. W= (F1-F2) x D
    = (300 – 200) x 750
    = 75 000 J
    = 75 KJ
b. W= (F1-F2) x D
    = (300-300) x 750
    = 0