As we already know that acceleration is a vector quantity which means that it has both direction as well as magnitude. It can also change given any one of the two or both (magnitude and direction) changes.
Yet in the high school physics textbook of mine, it explicitly states that “the direction of the velocity of a body can change when its acceleration is constant” as a true statement which seems to contradict the premise which we have established.
How can this be possible since acceleration should also change (not constant but become variable) if the direction of the velocity of a body changes given that in uniform circular motion the body is under variable acceleration as the direction of the body is changing and so not constant acceleration?
Is this case not similar to uniform circular motion? If not, please explain.
Best Answer
Projectile motion is motion under constant acceleration. Projectiles move on a parabolic path where both the magnitude and the direction of the velocity are continuously changing but the magnitude and the direction of the acceleration are not changing. The textbook is correct.