Page 145 - Active Science 5 Ebook and Activity

Mechanical Energy
Mechanical energy is the sum of potential and kinetic energy which

is associated with motion and position of the object.

Potential energy is the energy which is stored in an object. It has
the potential to perform work. For example, stored water in tanks
and dams.

Kinetic energy is the energy of motion whether it is vertical

or horizontal motion.

A moving truck and a bullet fired from a gun are examples of kinetic energy.

Loudspeaker
Electrical Energy
Electrical energy can be easily converted to other
forms of energy. It is the energy that is stored in

particles within an electric field. Fans, mobiles,
televisions, watches, etc. work on electrical energy.

Sound Energy
Sound energy is produced with the vibrations of Electric Pole

objects or matter. Musical instruments, radios and
loudspeakers are the sources of sound energy.
Windmill
Wind Energy
Wind energy is produced from the moving wind. Windmills convert wind energy into

electrical energy.

S imple Machines
Scissors Screw
A device that does work is a machine. In other words,
we can say that tools or instruments that make work
easier and efficient are called simple machines. Hammer
Machines do not increase the amount of effort put in,

but make the work easier by changing force or distance,
or by changing the direction of force. A pair of scissors, a
hammer, a pulley, a knife, an iron rod and a screw are Inclined Plane
examples of some machines which we use in our daily life.

Pulley
The machines may be simple or complex.
Some simple machines
Simple machines use mechanical or muscular force to work. All complex machines are
combination of two or more simple machines and generally use electrical energy or fuel to

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