posted by abu .
A ball rolling across a field with an acceleration of -0.5 m/s rolls 12.5 m and then comes to a stop after 8 seconds.
What was the ball's initial speed?
deceleration rate * time = Initial speed
= 4 m/s.
It should come to rest after rolling a distance (average speed)*(time) = 16 meters.
You have been given more infrmation that you need, and some of it is inconsistent.
Your deceleration rate also has the wrong units. m/s is not correct units for acceleration