Hello, I am a junior in high school now taking AP Physics B. i'm stuck on a series of questions regarding force: 1. Assume you are on a planet similar to earth where the acceleration of gravity is 10m/s^2 and the positive directions for displacement velocity and acceleration are upward. At t=0sec., an elevator is at a displacement of x=0 with a velocity of v=0m/s. A student whose weight is 400N stands on a scale in an elevator and records the scale reading as a function of time. The data is shown below: 0-5s--------400N 5-10s-------500N 10-15s------600N 15-20s-----0N a) Which direction is the force due to the scale? b) What is the mass of the student? c) Calculate the acceleration of the elevator during the 15-20s interval. d) Draw the a vs. t graph. e) What is the velocity of the elevator at t=20s? f) Draw the v vs. t graph. g) What is the displacement of the elevator above the starting point at the end of 20s? h) Draw the d vs. t graph. I was only completely sure about a and b, for a the direction is up and for b the mass is 40kg. I obviously don't want just answers, but steps and hopefully explainations to go along with it. Thank you.