What is the wavelength of a 3500 kg truck traveling at a rate of 66 km/h?

Answer 1

Either there is more information you have not provided or you did not mean to say wavelength. Thes question as stated has no answer.

Answer 2

E = hν = hc/λ = mc^2 = m0c^2/√(1 - v^2/c^2)
λ = (hc√(1 - v^2/c^2) / m0c^2
λ = (h√(1 - v^2/c^2) / m0c
λ = ((6.62606896*10^-34 J∙s)√(1 - (66/299,792,458)^2)/(3,500 m)(299,792,458 m/s)
λ ≈ 6.314911*10^-46 m