=h/mv where is wavelength, h is Planck's constant (6.626 x 10-34 kg m2/s), m is the mass, and v is the velocity 1. Calculate the wavelength of an electron traveling with a velocity of 6 x 106 m/s. An electron's mass is 0.00091 x 10-27 kg. 2. Calculate the wavelength of a baseball traveling with a velocity of 100.0 mi/hr (44.70 m/s). A baseball's mass is 0.142 kg