help-SHM and Exponential growth... (1 Viewer)

[kjj]

When we are doing questions in SHM where they just give us the acceleration (acceleration =-n^2x) and some other conditions, do we have to intergrate the acceleration to find the displacement in terms of time??
or can we quote the solution of x=a sin(nt+f)+b and sub in the condition to get the equation??


similarly, for exponential growth and decay, if we are give the rate of the growth {eg, dN/dt=k(N-P)}, can we quote the solution of N = P +Ae^kt and sub in the condition to get the equation??
or, do we need to get them by intergrating??

 

[McLake]

Originally posted by kjj
When we are doing questions in SHM where they just give us the acceleration (acceleration =-n^2x) and some other conditions, do we have to intergrate the acceleration to find the displacement in terms of time??
or can we quote the solution of x=a sin(nt+f)+b and sub in the condition to get the equation??

Depens on the question, normally yes ....

similarly, for exponential growth and decay, if we are give the rate of the growth {eg, dN/dt=k(N-P)}, can we quote the solution of N = P +Ae^kt and sub in the condition to get the equation??
or, do we need to get them by intergrating??

Again, depends on the question, but yes ....



Normally these equations are given anyway (especially with exp. growth and decay)

 

[kjj]

Re: Re: help-SHM and Exponential growth...

Originally posted by McLake


Depens on the question, normally yes ....

what do you mean by yes? =>we can quote th SHM equation or we need to derive it..........

Originally posted by McLake


Again, depends on the question, but yes ....

again, what do you mean by yes? =>we can quote the exponential equation or we need to derive it..........

 

[McLake]

Sorry, that wasn't very clear ...

Ok, normally you are asked in the question to derive the statement OR you are provided with it. If not "usually" you can quote it, just look at the question and see how much work needs to be done, if a lot needs to be done for litlle marks than just quote ...