Library / Tools / A-level physics equation calculator / Displacement from average velocity
Displacement from average velocity calculator
Motion
Displacement is the average velocity multiplied by time, when acceleration is constant.
s = ½ (u + v) t
This free calculator is for A-level physics. Choose the quantity you want to find, enter the other values with their units, and it shows the working in the layout used in exams, with the answer to the number of significant figures you choose. The values shown are an example. Change them to your own.
Quantity to find
Working
- Write the equations = ½ (u + v) t
- Substitute the valuess = ½ × (2 + 14) × 5
- Calculates = 40 m
- Give the answer to 3 significant figuress = 40.0 m
Worked example
Find s, the displacement. Given: initial velocity u = 2.00 m/s; final velocity v = 14.0 m/s; time t = 5.00 s.
- Write the equations = ½ (u + v) t
- Substitute the valuess = ½ × (2 + 14) × 5
- Calculates = 40 m
- Give the answer to 3 significant figuress = 40.0 m
Symbols and units
| Symbol | Quantity | SI unit |
|---|---|---|
| s | Displacement | m |
| u | Initial velocity | m/s |
| v | Final velocity | m/s |
| t | Time | s |
Displacement from average velocity: rearranged
- To find displacement: s = ½ (u + v) t
- To find initial velocity: u = 2s / t − v
- To find final velocity: v = 2s / t − u
- To find time: t = 2s / (u + v)
Exam tip
It does not need the acceleration, which makes it useful when acceleration is unknown.
Common questions
What is the formula for displacement from average velocity?
The equation is s = ½ (u + v) t, where s is the displacement (m); u is the initial velocity (m/s); v is the final velocity (m/s); t is the time (s).
What units should I use for displacement from average velocity?
In SI units: displacement in m, initial velocity in m/s, final velocity in m/s, time in s. The calculator also accepts common alternatives such as kilometres, grams or minutes, and converts them for you.
How do I rearrange s = ½ (u + v) t?
Rearranging gives these forms: to find displacement: s = ½ (u + v) t. to find initial velocity: u = 2s / t − v. to find final velocity: v = 2s / t − u. to find time: t = 2s / (u + v).
Practise displacement from average velocity questions
Press the button for a question with random numbers. Work it out on paper first, then type your answer.
Related
More motion equations: Speed, distance and time, Acceleration, Final velocity, Velocity squared, Displacement under constant acceleration, Momentum, Force and change in momentum, Centripetal force. See the full list on the a-level physics equation calculator page.