The force that holds two magnets together is the ONLY non-example of gravitational force. Except for the strong nuclear force, the weak nuclear force, the electrostatic force, the tidal force, the US Air Force, the force of destiny, the force of faith, the strength of one's convictions, and a few million other non-examples.
A non-example of force would be something that stay sill like a balloon in the air..... taste, smell, feel, texture, color, opinion, faith, hope, sincerity, honest, speed, momentum, altitude, volume, loudness, area, length, acidity, obesity, nationalism, current, resistance, viscosity, wavelength, flow, rate, frequency, albedo, diameter, age, temperature, acceleration, body mass index, salinity, specific, specific gravity, consciousness, intelligence, refraction index, mass, time, date rate, switching speed, libido, focal length, and latency are not force. And even there are many other things that also are not force, too.
Let's imagine a simple experiment. Imagine you have a long thick rope which one end is at your hands, and you start an oscillatory motion in it, moving your hand up and down. Then a friend of you take a picture of the rope in motion, looking at the rope laterally. Now let's find the wavelength and amplitude. Amplitude is "The distance from the center of the oscillation of the rope (when the rope was not in motion) to its high or low point", or the vertical displacement, in our experiment. On the other hand, wavelength is "The distance between one high point /low point and the next high point /low point". Take a look at a photo of a wave in your textbook and you will find the answer as well. ; )
