Part E and A particle moves with constant acceleration a. The expression v + at represents the particle's velocity at what instant in time? at time t = 0 at the "initial" time O when a time t has passed since the beginning of the particle's motion, when its velocity was v Submit Request Answer More generally, the equations of motion can be written as x(t) = x + v t + 2a (At) v(t) = v + a At. Here At is the time that has elapsed since the beginning of the particle's motion, that is, At = t-t, where t is the current time and ti is the time at which we start measuring the particle's motion. The terms and v are, respectively, the position and velocity at 0, which is a convenient t=t. As you can now see, the equations given at the beginning of this problem correspond to the case ti choice if there is only one particle of interest. =