Hello, I would like to determine the Wavelength of many different macroscopic objects for a theoretical project and I am having trouble understanding how to use the equation correctly due to relative velocities. When computing Wavelength = h/ Velocity * Mass I see example of calculating the wavelength of a baseball that is moving at 40 meters per second and weighs .14 kg. So I see that I need to use Meters per Second for velocity and KiloGrams or 1000x Grams for Mass. The trouble is that Velocity is relative, so this only gives you a wavelength of a baseball relative to the earth. I do not understand what the earth has to do with the wavelength of the baseball, are all wavelengths only relative? Is there no wavelength for the object itself? This means that the baseball has a huge amount of wavelengths depending on how you look at it. Also Plank's constant can be written in many different ways, and be different numbers. How would I know what number to use when I am talking of velocity in meters per second and mass in 1000x grams.