AQA A Level Maths: Mechanics复习笔记2.3.1 Deriving the suvat Formulae
Deriving the suvat Formulae
What is suvat?
- suvat?is an acronym for the five quantities used when?modelling?motion?in a?straight-line?with?constant?acceleration
- s?– displacement (from the starting point)
- u?– initial velocity
- v?– final velocity
- a?– acceleration
- t?– time
- All except time are?vector?quantities and can be?negative
- time is a?scalar?quantity
What are the suvat (constant acceleration) equations?
- The?five?equations for motion in a?straight line?are:
- The equations can?only be used?when the motion has?constant?acceleration
- All equations connect four of the five quantities
- Knowing any?three?allows a?fourth?to be found
- The equations are?provided?in the exam
How do I derive the suvat equations?
- The?four?equations that involve time can be derived from a?velocity-time?graph
- The velocity-time graph will be a?straight line?as the?acceleration?is?constant
- The fifth equation can be found by choosing any two of the equations and eliminating the t variable (see the worked example)
- Two?of the equations can also be derived using?calculus
- Velocity?is found by?integrating acceleration
- Displacement?is found by?integrating velocity
Worked Example
Use the constant acceleration equations
Exam Tip
- If you are asked to derive one of the formulae then the question will likely give you a hint as to which method to use. They may provide a velocity-time graph. Make sure you show each step and state any reasons such as the gradient of the graph being the acceleration.
- If the question does not ask you to derive the formulae, then you can use them freely without proof.
转载自savemyexams
国际竞赛真题资源免费领取
美高学分项目重磅来袭！立即了解
