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Energy Activity
If so instructed by your teacher, print out a worksheet page for these problems.
Background:
Potential
energy is stored energy. The chemical energy in a can of gas, the
energy in a compressed spring, and the energy in water behind a dam are
all examples of potential energy. Potential energy is also called energy
of position. In this case the formula for potential energy is:
E_{p} = m * g * h where E_{p}_{ }stands
for potential energy and is measured in joules, m stands for mass
and is measured in kilograms, g stands for gravity and equals 9.8
m/s^{2}, and h stands for height and is measured in meters.
Kinetic energy
is energy of motion. The formula for kinetic energy is: E_{k}
= 1/2 * m * V^{2} where E_{k }stands for
kinetic energy and is measured in joules, m stands for mass and
is measured in kilograms, and V stands for velocity and is measured
in m/s.
When
a glider loses altitude it converts potential energy into kinetic energy.
This is an example of the law of conservation of energy. When
potential energy is converted into kinetic energy, the velocity of the
plane or glider increases. The amount of increase can be calculated
by solving for velocity in the kinetic energy equation given above.
Problems:
 A model glider
has a mass of 1 kg. How much potential energy does it have 2 meters
off the ground?
 The same model
has a velocity of 2.2 m/s. How much kinetic energy does it have?
 If the same model
descends 2 meters and all it's potential energy is converted to kinetic
energy, what is the glider's change in velocity?
 A fullsized glider
has a weight of 4,900 N, while it's pilot has a weight of 825 N. If
it is 1,000 meters off the ground, how much potential energy do the
plane and pilot have?
 The same glider
from Problem 4 has a velocity of 35 m/s. How much kinetic energy does
it have?
 The same glider
from Problem 4 has a velocity of 35 m/s. The glider descends 900 meters.
What is it's new velocity?
 Compare the velocity
you calculated in Problem 6 to the speed of sound. Is this answer reasonable?
Why or why not

Related Pages:
Standards
Worksheet
Lesson Index
Aerodynamics Index


