What this tool answers
This page predicts the final velocity in a constant-acceleration model. It differs from finding an average from the net position change over a duration.
Formula
v = u + a × t.
Worked example: Four seconds of deceleration
An initial velocity of 9 m/s with acceleration −0.75 m/s² for 4 s gives final velocity 9 − 3 = 6 m/s. A negative acceleration does not automatically mean a negative final velocity.
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Limitations
Acceleration must remain constant over the interval. Interpret signs consistently. The equation does not include constraints that might end the motion earlier.
Frequently asked questions
Why can negative acceleration leave a positive final velocity?
The reduction in velocity can be smaller than the initial positive velocity.
What quantity does acceleration times time add here?
It adds the signed change in velocity over the interval.
Does this final-velocity expression require position inputs?
No. It uses initial velocity, constant acceleration and elapsed time.