a photon scatters in the backward direction (ϕ=180∘) from a free proton that is initially at rest. The outgoing photon has wavelength that is 10.0% larger than the wavelength of the incident photon. a) Calculate the wavelength of the incident photon. b) Calculate the kinetic energy gained by the proton in this scattering. c) Find the resulting speed of the proton. is this speed relativistic? (i.e is v > 0.1 c?)