Question

Plus and minus signs are used in one-dimensional motion to indicate direction. What is the sign of an acceleration that reduces the magnitude of a negative velocity? Of a positive velocity?

a) Negative, positive
b) Positive, negative
c) Positive, positive
d) Negative, negative

Answer 1

The sign of acceleration needed to reduce the magnitude of a negative velocity is positive, and to reduce the magnitude of a positive velocity it must be negative.

Step-by-step explanation:

Plus and minus signs in one-dimensional motion represent direction, with plus generally indicating rightward motion and minus indicating leftward motion. If a negative velocity is to be reduced in magnitude, the acceleration must be in the opposite direction to the velocity, meaning it should be positive. Conversely, to reduce the magnitude of a positive velocity, the acceleration needs to be negative, acting in the opposite direction. Therefore, the sign of acceleration that reduces the magnitude of a negative velocity is positive, and the sign of acceleration that reduces the magnitude of a positive velocity is negative.