The student drops her pen just before the elevator reaches the second floor.
(4) As the pen is dropped, what is the acceleration of the pen with respect to the elevator floor?
Since the pen is accelerating with the elevator and the student, the only acceleration apparent to the student is the acceleration due to gravity = -9.8 .
(5) As the pen is dropped, what is the acceleration of the pen with respect to an observer on the first floor?
The observer on the first floor sees the net acceleration, which includes the upward acceleration of the elevator. Therefore, the observer sees an acceleration of -8.8 .
