Categorize the following motion as being either an example of positive(+ve) or negative(-ve) acceleration.
i. Speeding up the motion =
ii. Slowing down the motion =
+ve , -ve , -ve , +ve
We know that,
a=vf−vit, where, vf is the final velocity and vi is the initial velocity.
For speeding up, magnitude wise vf>vi and for slowing down, vi>vf .
So, when an object is speeding up it means the accelaration is in the direction of motion hence acceleration is positive. If an object is slowing down, then its acceleration is in the opposite direction of its motion, its final velocity will be less than its initial velocity and hence the acceleration will be negative.