1. The problem statement, all variables and given/known data A flying saucer decelerates uniformly from 20 m/s [E] to 50 m/s [W] in 9 seconds. Find the velocity for the 9.0 interval. 2. Relevant equations Velocity = acceleration x time or Velocity = displacement/time 3. The attempt at a solution Velocity1 = 20 m/s [E] Velocity2 = 50 m/s [W] Time = 9 s Velocity = 30 x 9 = 270 However, the answer should be 15 m/s [W].