Download Gravitational Potential Energy

GRAVITATIONAL POTENTIAL ENERGY
MR. T
VIDEO
VIDEO
POTENTIAL ENERGY
An object can store energy as the
result of its position.
The energy possessed by a body by
virtue of its position relative to others,
stresses within itself, electric charge,
and other factors.
KINETIC ENERGY
Kinetic energy is the energy of motion.
Potential energy is stored energy. (no motion).
TODAY WE ARE TALKING ABOUT ..
Gravitational potential energy!!!!
Gravitational potential energy is the energy stored in an object as
the result of its vertical position or height.
The energy is stored as the result of the gravitational attraction of
the Earth for the object
GRAVITATIONAL POTENTIAL ENERGY
There is a direct relation between gravitational potential energy
and the mass of an object. More massive objects have greater
gravitational potential energy.
There is also a direct relation between gravitational potential
energy and the height of an object. The higher the height the more
potential energy.
GRAVITATIONAL POTENTIAL ENERGY
LETS LOOK AT THE EQUATION
PEgrav = m • g • h
In the above equation, m represents the mass of the object, h
represents the height of the object and g represents the
gravitational field strength (9.8 N/kg on Earth) - sometimes
referred to as the acceleration of gravity.
IMPORTANT
In this class you will not be asked to do calculations on a test or
quiz.
BUT you should be able to tell me if the Gravitational potential
energy would decrease or increase if I change variables in the
equation.
EXAMPLE
A rock that has a mass of 20kg is on a cliff that is 20m high. How
would the Gravitational potential energy change if it was on a cliff
that was 30m high?
ANSWER
The GPE would increase because h in the equation
PEgrav = m • g • h is increasing.
EXAMPLE
A rock that has a mass of 20kg is on a cliff that is 20m high. How would the
Gravitational potential energy change if it was on a mass of the rock only 15kg?
ANSWER
The GPE would decrease because the m in the equation
PEgrav = m • g • h is decreasing.
GPE IN A PENDULUM
PENDULUM
At which point(s) does the pendulum
have the most potential energy?
At which point(s) does the pendulum
have the most kinetic energy?
Name two point where the pendulum is
increasing in kinetic energy.
PENDULUM
At point “D” the pendulum is
_______________ kinetic
energy because it is
__________________ its
speed. Meanwhile it is
_______________ potential
energy because it is
__________________ its
height.