Help with 3,4,5

3. A ball is thrown straight up into the air with a velocity of +23.5 m/s. After 4.5 s, the velocity of the ball is A) -44.1 m/s B) -20.6 m/s +44.1 m/s D +20.6 m/s 4. If an object starts from rest and rolls down an inclined plane a distance of 3.1 m in 0.95 s, then the object's acceleration is A) 5.16 m/s2 B) 9.81 m/s2 C) 6.87 m/s2 D) 4.65 m/s2 5. Garrett runs down a hallway due north 80.0m, then turns, and runs down another hall due west for 20.0m. What is his displacement? A) 100m B) 100m northwest C) 82.4m D) 82.4m [14 W of N]