• The SUVAT equations are the equations of motion used for objects in constant acceleration
• They contain the following variables:
  • s??= displacement (m)
  • u?= initial velocity (m s-1)
  • v?= final velocity (m s-1)
  • a?= acceleration (m s-2)
  • t?= time (s)

   

• The 4 SUVAT equations are:

• These are all given on the data sheet
• All the variables, apart from?time?t, are vector quantities
  • This means they can either be positive or negative depending on their direction

   

• The key terms to look out for are:
  • 'Starts from rest', or if the initial velocity is not mentioned, this means?u?=?0
  • 'Starts from rest' also means that?t?= 0
  • If an object is only 'falling due to gravity' then?a?=?g?=?9.81 m s-2
  • It doesn't matter which way is positive or negative for the scenario, as long as it is consistent for all the vector quantities
    • For example, if downwards is negative then for a ball travelling upwards,?s?must be positive and?a?must be negative

     

   

• SUVAT equations are used for motion with?constant acceleration?in a straight line
  • For example, an object falling in a uniform gravitational field without air resistance

   

How to Use the SUVAT Equations

• Step 1:?Write out the variables that are given in the question, both known and unknown, and use the context of the question to deduce any quantities that aren’t explicitly given
  • e.g. for vertical motion?a?= ± 9.81 m s–2, an object which starts or finishes at rest will have?u?= 0 or?v?= 0

   

• Step 2:?Choose the equation which contains the quantities you have listed
  • e.g. the equation that links?s, u, a?and?t?is s = ut + ?at2

   

• Step 3:?Convert any units to SI units and then insert the quantities into the equation and rearrange algebraically to determine the answer
• Sometimes the question may have to be split into two, where the SUVAT equations will have to be used twice
  • For example, if there are two masses connected over a pulley and one mass continues moving after the other has stopped