physics
posted by alexa .
A student stands on a bathroom scale in an elevator at rest on the 64th floor of a building. The scale reads 845 N. As the elevator moves up,the scale reading increases to 940N,then decreases back to 845N. The acceleration of gravity is 9.8 m/s^2.
Find the acceleration of the elevator. Answer in units of m/s^2.
As the elevator approaches the 74th floor, the scale reading drops as low as 789N.
What is the acceleration of the elevator? Answer in m/s^2

Hint: A newton is a kilogram per m/s^2.
Figure out the mass of the student.