The centripetal force (of gravity) on a satellite in orbit is an
unbalanced force (because there's no equal force pulling
the satellite away from Earth), changes the direction of the
satellite (into a closed orbit instead of a straight line), and
always acts toward the center of whatever curve the satellite
happens to be on at the moment.
I believe the website www.asanet.org will help (:
Hydrogen, helium, and carbon.
The sound is perceived as louder if the amplitude increases, and softer if the amplitude decreases. ( for amplitude)
Since sound at all frequencies has the same speed in air, a change in frequency means a change in wavelength. ( for frequency)