Which of the following has an acceleration in the same direction as the object's motion?
1. Vi=3.5m/s [east]; Vf=7.5m/s [east]
2. Vi=45km/h [north]; Vf=60km/h [north]
3. Vi=15m/s [right]; Vf=10m/s [left]
Textbook Ans: 1 and 2
Can someone explain why? Cause I don't know how to get the answer. Thanks very much.
If the speed is increasing in the direction the thing is going, that qualifies.
Number 3 is reversing direction, moving right at the beginning but accelerating left.