If the velocity of an object changes, then
1. its speed must change.
2. None of these
3. it is accelerating.
4. All of these
5. its direction of motion must change.
1. NO could be going in a circle at constant speed
2. not sure yet
3. YES, acceleration is rate of change of velocity vector
4. Nope, but we know that 2 is false now
5. NO!! You can be accelerating straight ahead.