Question

When is the acceleration taken as negative​

Answer 1

Explanation:

According to our principle, when an object is slowing down, the acceleration is in the opposite direction as the velocity. Thus, this object has a negative acceleration. In Example D, the object is moving in the negative direction (i.e., has a negative velocity) and is speeding up.

Answer 2

Answer:

acceleration is taken to be negative when the object is retarding i.e. the velocity of the object is decreasing with time

Explanation:

since acceleration is defined as the rate of change of velocity with time its sign depends on how the velocity is changing (increasing or decreasing)

NOTE - the most easy way to identify the sign of acceleration is by comparing the values if initial velocity and final velocity ..if final velocity < initial velocity then the sign of acceleration is negative