I ll simplyfy it
a particle has a velocity X...
now it is said to have a constant velocity A...
So the velocity of the particle is X+A in the first second and X+A+A in the second second and so on...
just that the addition in velocity is a constant...
Constant acceleration means that an object has a velocity that keeps changing constantly. The amount of acceleration is the same.
So, if a car had constant acceleration, and it starts moving from a stop (in which case, when stopped it had a velocity of 0) then say at:
1 sec after moving its going 2 miles an hour;
2 sec after moving its going 4 miles an hour;
3 sec after moving its going 6 miles an hour;
4 sec after moving its going 8 miles an hour;
and so on.
So the velocity (the speed of the car, in this case in miles an hour) is constantly changing (its going up)- but the amount of acceleration stays the same, at 2 miles a second, I.e its constant.
Hope that makes sense!
Cinthia, The previous examples are correct, however, remember that acceleration is BOTH a velocity AND a direction. (Ignoring air resistance) a ball dropped off a cliff has a constant acceleration due to gravity and will keep falling faster until it hits the ground. ALSO, a race car going exactly 100 MPH on an exactly circular track is also undergoing constant acceleration because its Direction is constantly changing by the same amount.
constant acceleration means that the acceleration doesn't change.
^^^ In the case of the ball, its acceleration will stop if it reaches terminal velocity however.
It means the acceleration increases at a constant rate, or there is no change in velocity.