An electron is initially at rest in a uniform electric field having a strength of 1.85 × 106 v/m. it is then released and accelerated by the presence of the electric field. 50% part (a) what is the change in the electron’s kinetic energy, in kiloelectron volts, if it travels over a distance of 0.25 m in this field? δk = - 4.63 * 105|

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".