<span>At an instant when the displacement is equal to a/2,
Potential energy U = 1/2ka(square) where a is displacement.
when a= a/2
U = 1/4ka(square)
U = E/4
Potential Energy = 1/4 Total energy</span>
Answer:
a) T² = (
) r³
b) veloicity the dependency is the inverse of the root of the distance
kinetic energy depends on the inverse of the distance
potential energy dependency is the inverse of distance
angular momentum depends directly on the root of the distance
Explanation:
1) for this exercise we will use Newton's second law
F = ma
in this case the acceleration is centripetal
a = v² / r
the linear and angular variable are related
v = w r
we substitute
a = w² r
force is the universal force of attraction
F = 
we substitute

w² = 
angular velocity is related to frequency and period
w = 2π f = 2π / T
we substitute

the final equation is
T² = () r³
b) the speed of the orbit can be found
v = w r
v = 
v = 
in this case the dependency is the inverse of the root of the distance
Kinetic energy
K = ½ M v²
K = ½ M GM / r
K = ½ GM² 1 / r
the kinetic energy depends on the inverse of the distance
Potential energy
U =
U = -G mM / r
dependency is the inverse of distance
Angular momentum
L = r x p
for a circular orbit
L = r p = r Mv
L =
L =
The angular momentum depends directly on the root of the distance
All of the electromagnetic energy radiated from the sun (and from
other stars) is the product of nuclear fusion in its core.
The easiest way to build a unit for energy is to remember that
'work' is energy, and
Work = (force) x (distance).
So energy is (unit of force) x (unit of distance)
[Energy] = (Newton) (meter) .
'Newton' itself is a combination of base units, so
energy is really
(kilogram-meter/sec²) (meter)
= kilogram-meter² / sec² .
That unit is so complicated that it's been given a special,
shorter name:
Joule .
It doesn't matter what kind of energy you're talking about.
Kinetic, potential, nuclear, electromagnetic, food, chemical,
muscle, wind, solar, steam ... they all boil down to Joules.
And if you generate, use, transfer, or consume 1 Joule of
energy every second, then we say that the 'power' is '1 watt'.