HL Math Paper 2- 24 Hours Later...
Discussion forum for International Baccalaureate students.
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Re: HL Math Paper 2- 24 Hours Later...I got v=arctan(pi/4-t)(Original post by johndoe04)
What did you get for the applications question? Writing an equation for v in terms of t? -
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Re: HL Math Paper 2- 24 Hours Later...(Original post by Hyaline)
For the ball bouncing did you guys use ar^n or ar^n-1 there was a bit debate in my school about it ^^.
n-1.
Nooooooooooooooooo. Arctan? How? urghhhhh
I thought that v^2 = dv/dt since they're both acceleration? :/ -
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Re: HL Math Paper 2- 24 Hours Later...can you help me understand how you got that? I remember thinking that you couldn't just integrate straight away.....(Original post by Saymyname!)
I got v=arctan(pi/4-t) -
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Re: HL Math Paper 2- 24 Hours Later...The equation was something like, v^2 +dv/dt - 1 = 0. How did you go from there?(Original post by Hyaline)
if you got v^2 you rearranged it wrong at the start :P. -
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Re: HL Math Paper 2- 24 Hours Later...I said that since velocity is ds/dt, then v^2 is d^2s/dt^2 which equals acceleration. And dv/dt is also acceleration. At the time, i thought it made sense. Although....yeah, when i left the exam hall, i felt that maybe it wasn't correct. Urgghghghghghghghghghg(Original post by Hyaline)
if you got v^2 you rearranged it wrong at the start :P. -
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Re: HL Math Paper 2- 24 Hours Later...Yup.(Original post by Hyaline)
In the bouncing ball question n was the number of bounces right ^^.
Sigh. At least i got that one correct. -
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Re: HL Math Paper 2- 24 Hours Later...argh. yeah. damn. that makes sense.(Original post by Hyaline)
you get 1/1-v^2 dv=dt then integrate both sides according to the equation you posted....... I don't remember whether there were boundaries.
Suddenly, i feel really, really bad. -
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Re: HL Math Paper 2- 24 Hours Later...Need more opinions on the ar^n ar^n-1 thing. My logic was that if n is the number of bounces, after 1 bounces where n=1, the ball would reach a height of 3.8 not 4, so it works in a similar way to compound interest.
Initially I assumed that 4 being the first term would equal 4*0.95^(1-1)=4. But if n represents bounces (what else could it represent :P), then after the first bounce the ball wouldn't come back to a height of 4m, it would reach 3.8m sincd the question said 0.95 of the previous height- so I used ar^n instead......... I'm worried about this question now
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Re: HL Math Paper 2- 24 Hours Later...No, wait. Actually, I remember putting 3.8 down after the first bounce since it makes absolute sense that the ball loses energy after the first bounce, and therefore reaches a lower height. Because it will never equal 4.(Original post by Hyaline)
Need more opinions on the ar^n ar^n-1 thing. My logic was that if n is the number of bounces, after 1 bounces where n=1, the ball would reach a height of 3.8 not 4, so it works in a similar way to compound interest.
Initially I assumed that 4 being the first term would equal 4*0.95^(1-1)=4. But if n represents bounces (what else could it represent :P), then after the first bounce the ball wouldn't come back to a height of 4m, it would reach 3.8m sincd the question said 0.95 of the previous height- so I used ar^n instead......... I'm worried about this question now
