1. The problem statement, all variables and given/known data An object changes its velocity from 10 m/s [W] to 20 m/s [W] in 4.0s. An object changes its velocity from 20 m/s [W] to 10 m/s [W] in 4.0s. 2. Relevant equations N/A 3. The attempt at a solution I'm thinking the first one is positive acceleration and the other one is negative acceleration (people also say deceleration but my teacher told us to use the term negative acceleration) because if you're moving west, west is negative so isn't -10 greater than -20? I'm awful at physics so I don't know if I'm thinking this through correctly.