Acceleration and SUVAT Calculator
Enter any three of displacement, start speed, final speed, acceleration and time. You get the other two, including both answers where there are two.
Fill in exactly three boxes and leave two empty. Take one direction as positive, so a body thrown upwards under gravity has a = -9.80665.
Worked examples
From rest
u = 0, a = 2, t = 5
s = 25 m and v = 10 m/s
s = half x 2 x 25.
Ball thrown up
u = 20, a = -9.8, s = 15
v = 10.3 m/s going up, -10.3 m/s coming down
v squared = 400 - 294.
About Acceleration and SUVAT Calculator
The SUVAT equations describe motion in a straight line with constant acceleration. The letters stand for displacement s, initial speed u, final speed v, acceleration a and time t. There are five of them, and any three of the quantities fix the other two, so every problem in the topic comes down to picking the equation that has your three knowns and one unknown. This calculator does the choosing for you and also covers the simple case of acceleration as a change of speed over time.
Enter the three values you know and the page works out the other two. Some problems have two correct answers. A ball thrown upwards passes the same height on the way up and on the way down, and the page lists both. It refuses combinations that cannot happen, such as a speed squared that would be negative. Choose a direction as positive and keep to it, so gravity acting downwards becomes minus 9.80665 metres per second squared.
How to use Acceleration and SUVAT Calculator
- Decide which three of s, u, v, a and t you know.
- Enter them, choosing units such as miles per hour or kilometres, and leave the other two boxes empty.
- Read the two missing values, and both solutions if the problem has two.
- Use a negative sign for quantities pointing the opposite way to your positive direction.
Common uses
- A-level and GCSE mechanics problems
- Finding the braking distance of a car from its speed and deceleration
- Working out how long a vehicle takes to reach a speed
- Finding how high a thrown object rises
Frequently asked questions
What are the SUVAT equations?
They are v = u + at, s = ut + half at squared, s = (u + v)t / 2, v squared = u squared + 2as, and s = vt minus half at squared. They apply only when acceleration is constant.
Why are there sometimes two answers?
When time or final speed is found from a square root, both a positive and negative root can be valid. A ball thrown up reaches a given height going up and again coming down, with opposite velocities.
How do I find acceleration from speed and time?
Enter the start speed, final speed and time and leave acceleration empty. The page returns a = (v - u) / t, and the distance covered as well.
Can I use it for falling objects?
Yes. Use a = 9.80665 with downwards as positive, or minus 9.80665 with upwards as positive. Air resistance is ignored.
What does a negative displacement mean?
It means the object ended up on the opposite side of its starting point from the direction you called positive.