Aperson is standing on an elevator initially at rest at the first floor of a high building. the elevator then begins to ascend to the sixth floor, which is a known distance h above the starting point. the elevator undergoes an unknown constant acceleration of magnitude a for a given time interval t. then the elevator moves at a constant velocity for a time interval 4t. finally the elevator brakes with an acceleration of magnitude a, (the same magnitude as the initial acceleration), for a time interval t until stopping at the sixth floor (a) make a sketch of the velocity v(t) of the elevator as it travels to the sixth floor. your sketch should be qualitatively correct: it should have the right shape, but the vertical scale need not be accurate. hint: thinking about the graphical representation of v(t) leads to a much easier solution for part b. (b) find the value of a, the magnitude of the acceleration, in terms of h and t.