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I used the equation v=sqrt((GM)/r). That's how I worked out centripetal force in question 12. I know it sounds like a very long way of doing question 13 but I'm just wondering why i don't get the same answer as you would get using Kepler's Law of Periods... Thanks though!

Hey guys, for question 13, I didn't use Kepler's Law of Periods. Instead I used v=2(pi)r/T and used the velocity from question 12. And so I got C for q. 13. Why is this method wrong, will someone tell me please?

That's a really well said analogy there Carrotsticks! Thanks heaps for that! I guess I can accept that maximum acceleration occurs at endpoints. Will this question of maximum acceleration ONLY be asked for simple harmonic motion?

Thank you very much Carrotsticks! :) Just one question, what exactly is the difference between maximum velocity and maximum acceleration? It seems the same...

A particle is moving in a straight line with Simple Harmonic Motion. If the amplitude of the motion is 4cm and the period of the motion is 3 seconds, calculate: i. the maximum velocity of the particle; ii. the maximum acceleration of the particle; iii. the speed of the particle when it is 2cm...

You observe the gradient/slope of the graph given to you. If you were to sketch the primitive of the graph, for eg. if the original graph had a +ve gradient, you would draw a primitive with y">0 (concavity) so both gradients are equal.

Yeah forgot that was a given! Anyway I tried to use another method by letting u=sqrt(x) and it worked.

How did you guys know it would involve a trig substitution?

Thank you very much Dylanamali! :)

Wow Spiralflex! Thank you so much for the effort! Okay I guess substitution method does not seem to be reliable for this case, right? I'm going to adopt this new concept of integrating a sqrt function. Thank you!!! :)

Thanks Carrotsticks. One problem though, I'm used to substitution method when splitting up the fractions. But I can't seem to apply substitution or am I not seeing a trick behind it?

Could someone help me out on another question please? \int&space;\frac{x+1}{\sqrt{1-x-x^2}}dx

Damn I didn't see Carrotsticks' post. Yeah I think I'm more comfortable with substitution method. Thank you SpiralFlex and everyone else who contributed. :)

Should that really be assumed knowledge? Because I'm not familiar with it

Thank you but how do you integrate the first part of the equation with x as the numerator using inverse trig? :S

Please help me integrate using inverse trig \int&space;\frac{x+1}{\sqrt{4-x^2}}dx

Ohhh yeah I see, I see... whatever the derivative of f(x) is, when you integrate it, it is still f(x). Thank you very much nightweaver066 for your help and your help for my other post.

Thanks nightweaver066 but I have a question... can you tell me how you can integrate d/dx (xe^x)? Does the integration sign and d/dx cancel out?

Hey SpiralFlex, the answer is pi/32 not pi/12 because pi/4 will multiply with 1/8 :)

How do I do the second part of this question? Can someone help me please?