1. The problem statement, all variables and given/known data An object is thrown vertically upward at 35 m/s. The velocity of the object 5.0 seconds later is: 2. Relevant equations vf=vo-gt 3. The attempt at a solution g=9.8 m/s vo=35 m/s t=5s vf=? vf=35-(9.8)(5)=14 m/s down I know this is the correct answer, but I'm confused about why you choose the equation above. The first time I worked this problem I tried to use vf=vo+gt. Could someone please explain to me why this would be wrong? Is it maybe because the acceleration is negative?