If the acceleration is constant and the motion is in a straight line then simplifications become possible. We can define five variables:

– displacement

– initial velocity

– final velocity

– acceleration

– time

and write down five equations that link these five variables:

(1)

(2)

(3)

(4)

(5)

Given any three of the others can be calculated by completing a table of the variables and using the suvat equations.

Example: A particle accelerates from rest to a speed of 3m/s in 5 m. Find the final velocity and the time taken.

(since the particle accelerates from rest)

(Note the units are all SI units).

We can find a using equation (3):

Now we can find t using for example, (1):