SUVAT Equations – AS Physics Revision

Uniformly Accelerated Motion

  • SUVAT wasn’t a person. It’s an acronym
  • S – displacement
  • U – initial velocity
  • V – final velocity
  • A – acceleration
  • T – time
  • The acronym comes with a set of equations which allow you to work things out about objects undergoing constant acceleration
  • Please note that all of those quantities (except time) are vectors, so direction is important
  • (I guess you could say time is a vector, which only ever points to the future)

How To Use

  • Write SUVAT, vertically
  • Write all the values you know next to their respective letters
  • There will usually be two letters you don’t know
  • One of these, you want to find
  • The other, you don’t have and don’t need – ignore it
  • Choose the SUVAT equation which doesn’t feature the letter you’re ignoring
  • Rearrange the chosen equation to make the letter you want to find the subject
  • Substitute the known letters in
  • Work out the answer

The Equations

  • They’re given to you in the formulae/constants booklet in the exam… I think
  • You don’t have to memorize them, unless you’re doing Mechanics 1 in A2 Maths, apparently
  • Anyway, there are four: one with no letter ‘a’, one with no ‘s’, one with no ‘t’ and one with no ‘v’
  • (They’re kinda the same equation anyway – someone had to do a lot of rearranging and substitution to eliminate some of the letters)
  • I shall now attempt to type the equations written in my book…
  • s = (v + u) / 2 * t
  • a = (v – u) / t
  • v^2 = u^2 + 2 * a * s
  • s = u * t + 0.5 * a * t^2

Tips

Figure A: An object is fired upwards, reaches ...

Figure A: An object is fired upwards, reaches its apex, and then begins its descent under a constant acceleration. Note: The equations described here holds for object fired from ground and should not be mistaken with this picture. (Photo credit: Wikipedia)

 

  • You’re not necessarily explicitly told the quantities you have to use
  • If something’s starting from rest, for instance, you know its initial velocity is zero
  • If something’s falling under gravity, its acceleration is g (the y component, anyway)
  • g is the acceleration gravity applies to all falling objects (on earth, anyway)
  • It’s about 9.81, or 9.8 m s^-2 (metres per second per second)
  • Since it’s all to do with vectors, you might have to SUVAT the x components and the y components separately
  • In that case, write the x components on the left of your vertical SUVAT and the y components on the right, to avoid confusion
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About Matt

I like writing, filmmaking, programming and gaming, and prefer creating media to consuming it. On the topic of consumption, I'm also a big fan of eating.
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