Hypothetically, a particle p of mass M is sitting at velocity v. Assuming M = 0, and the vi of p is 0 m/s, 0 seconds passes and vf 100 m/s is reached. Since time t is 0, acceleration cannot exist, as no t has passed between the vi and vf states. And, knowing that a = (vf - vi)/ Δt, a = (100 -...