A set of keys slides along the floor, coming to rest 1.4 meters from where it started. If the initial speed of the keys was 2.1m/s , then the acceleration of the keys is ?
For constant acceleration, Vf^2=Vi^2+2as. Where Vf is final velocity, Vi is initial velocity, a is acceleration, and s is distance. For the keys, Vf=0. (2.1)^2+2a(1.4)=0 Solving for a I get -1.575m/s^2.
