2kg weight is suspended on a tension scale that measures in Newtons. The elevator is moving at constant velocity up of 10m/s. Its velocity is then uniformly reduced to zero in 4 seconds. So that it comes to rest in 4 seconds. What does the scale read during those 4 seconds. --------- Using frame of reference with positive down: (That way gravity's acceleration is positive.) Using Kinematics: Vf=Vi*t+1/2a*t^2 Therefore: a=(-2Vi)/t=-5m/s^2 Applying F=ma: Ftension+Fgravity=ma -Ft+mg=ma Ft=mg-ma=2*9.8-2*(-5)=29.6N My books says: 14.6N What'd I do wrong?