
1)
What is kinetic energy ?
An object
owns kinetic energy when it's moving: kinetic energy is the motion
energy.
Its symbol is KE and its unit is joule (J).
This energy
depends on speed: the faster an object moves, the more it has kinetic
energy
A stationary object therefore does not have kinetic energy.
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2)
Kinetic energy of a falling object
A falling
ball is going faster and faster until it reaches the ground. As speed
increases, kinetic energy increases too so where does this energy come
from ?
While the ball is dropping, the height decreases, therefore potential
energy decreases too:
Potential energy is converted into kinetic energy.
When the ball reaches the ground, all its initial potential energy has
been converted in kinetic energy and then this kinetic energy is
transfered to the ground.
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