Answer to Question #119662 in Physics for Myriam

Question

Can you correlate the sign of velocity with the sign of acceleration in order for an object to accelerate or decelerate?

Answer 1

Yes. If the object accelerates, its acceleration is positive. If the object decelerates, its acceleration is negative. In order to successfully use this rule, make sure that the object moves in the positive direction of the reference axis.

For example, assume that the object falls along y-axis that point downward. Its acceleration will be positive. If another objects is launched upward in the same system of coordinates, it will decelerate, and this object's acceleration will be negative.