If you throw a ball, and it slows from 0.33 m/s to 0.13 m/s over a period of 5 seconds, what is the acceleration? The change in velocity was from 0.33 m/s to 0.13 m/s and the change in velocity took 5 seconds. Using the equation for acceleration:
Acceleration = (0.13 m/s - .33 m/s) ÷ 5 seconds
(always subtract the original velocity from the new one, no matter which is larger)A = -0.2 m/s ÷ 5 seconds
A = -0.04 m/s2
Since the ball slowed down instead of getting faster, we write the answer with a minus sign. This tells you that the ball had a negative acceleration.
Note that for simplicity’s sake, we are using examples that don’t involve change in direction of the object. We’ll save that for future physics courses!
Negative Acceleration
What does it mean if an object has a negative acceleration?
If an object has a negative acceleration it means it is slowing down.
