This is where we have to admit that gravitational potential energy is
one of those things that depends on the "frame of reference", or
'relative to what?'.
Potential energy = (mass) x (gravity) x (<em>height</em>).
So you have to specify <em><u>height above what</u></em> .
-- With respect to the ground, the ball has zero potential energy.
(If you let go of it, it will gain zero kinetic energy as it falls to
the ground.)
-- With respect to the floor in your basement, the potential energy is
(3) x (9.8) x (3 meters) = 88.2 joules.
(If you let go of it, it will gain 88.2 joules of kinetic energy as it falls
to the floor of your basement.)
-- With respect to the top of that 10-meter hill over there, the potential
energy is
(3) x (9.8) x (-10) = -294 joules
(Its potential energy is negative. After you let go of it, you have to give it
294 joules of energy that it doesn't have now, in order to lift it to the top of
the hill <em>where it will have zero</em> potential energy.)
If the two waves have the SAME FREQUENCY and are exactly
out of phase (180° apart), then the resultant wave will have the
same frequency and an amplitude of 1 unit.
If the two waves do not have the SAME FREQUENCY, then their
relative phase is meaningless.
<h2>
Answer:</h2>
<h2>Comet:</h2>
It is a celestial body constituted by ice, dust and rocks that orbit around the Sun, after having been altered by the Oort cloud; following different trajectories that can be highly eccentric elliptical (periodic trajectories), parabolic or hyperbolic.
One of the main characteristics of a comet is that it travels quite fast, on its way around the Sun and has a long tail, which always go in the opposite direction to the Sun (due to the radiation pressure of sunlight).
<h2>Asteroid:
</h2>
It is a small rocky body (smaller than a planet and larger than a meteoroid). Most of these bodies are orbiting between Mars and Jupiter in the region known as the asteroid belt; while others accumulate at Jupiter's Lagrange points, and others cross the orbits of the planets.
<h2>Meteoroid:
</h2>
It is a fragment of the celestial body that moves through space, which is smaller in size to an asteroid. If it gets to enter the atmosphere of the Earth, it will start to burn by friction with it (combustion) and it will be called a meteor, while if it hits the surface, it will be called a meteorite.
