Are we allowed to quote the cartesian equation of projectile motion? (1 Viewer)

[hayabusaboston]

THat is, in an exam, can we simply quote y=(-gx^2)/(2U^2cos^2(th))+xtan(th) or do we have to write out all the components then derive this?

 

[SpiralFlex]

There should be clear enough instructions for you to see if you need to derive it or not. If not it will say on the side DO NOT PROVE

 

[hayabusaboston]

There should be clear enough instructions for you to see if you need to derive it or not. If not it will say on the side DO NOT PROVE

O cos I saw a question where it didnt say anything and in solutions it just quoted this and was wondering how we'd know whether or not we were allowed to quote.

 

[Carrotsticks]

O cos I saw a question where it didnt say anything and in solutions it just quoted this and was wondering how we'd know whether or not we were allowed to quote.

You can look at the number of marks it is worth. If it is say 4 marks for a 'Find the values of theta such that the particle passes through XXX point' then it may be worth deriving.

However, keep in mind that some schools allocate their marks very poorly (I've seen 6 marks allocated to a selective schools Auxiliary Angle problem, and it was just a standard one) so when doing past trials, just quote it.

However, for your actual exam, ask your teacher beforehand if you can just quote it.

As for the actual HSC, look at the number of marks its worth and check whether they have provided it already. If not, and it's worth a fair few marks, just derive it. Doesn't take long anyway.

 

[braintic]

THat is, in an exam, can we simply quote y=(-gx^2)/(2U^2cos^2(th))+xtan(th) or do we have to write out all the components then derive this?

The answer is NO.

 

[namelyanonymous]

The answer is NO.

No to which part of the question?

 

[braintic]

No to which part of the question?

No, you may not just quote the cartesian equation. The only projectile motion formulae you can quote are x''=0 and y''=-g. Anything else must be derived or will be given to you.

 

[mynameiscool]

can we quote formulas for max range and max height?

 

[Makematics]

can we quote formulas for max range and max height?

no