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Mechanics 1 P42 2014; Discussion!

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xtremeuser12345

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17194 said:
Okay so let's suppose that the equation you ended up with 's=3/10 T^5/3 - 1.6' is correct for the entire motion of the body, because at t=8 you get the same value of displacement i.e 8m. That means that this equation is applicable to the entire motion. So try it with a different time e.g t=4s. In the linear motion if you substitute the value of t=4s you will end up with a displacement of s=2m (s= 1/2 (0.25) (4^2). Substitute this value into your 'correct' expression of s and you end up with s=1.42m, clearly showing that this is not a universal expression for the entire motion. The motion had to be treated as two separate parts, from t=0 to t=8 and then t=8 to t=27. That is why when the second motion starts at t=8, which is equal to t=0 for motion 2.
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that equation only is applicable for t=8.finding the constant makes it as if the motion started from t=0 instead of t=8.the particle/car only shares the same distance,speed,acceleration at t=8,and not at any other time so if it shares the same distance of the particle at t=8 having constant acceleration,then u can directly sub t=27 in the equation as long as u found c.there hundreds of questions like this one i did everything from 2001-2013 the way of the answers are in the 2 ways ive listed.
 
thementor

thementor

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xtremeuser12345 said:
that equation only is applicable for t=8.finding the constant makes it as if the motion started from t=0 instead of t=8.the particle/car only shares the same distance,speed,acceleration at t=8,and not at any other time so if it shares the same distance of the particle at t=8 having constant acceleration,then u can directly sub t=27 in the equation as long as u found c.there hundreds of questions like this one i did everything from 2001-2013 the way of the answers are in the 2 ways ive listed.
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yes the answer is 71.3m Well good luck for your next papers
 
Oishee Asif

Oishee Asif

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1597.2217 said:
JazakAllah Khair! I got question 5 correct, and question 6 part a till the deceleration, didn't have time for part b. I guess the exam wasn't bad afterall!
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Haha. That's good, mashaaAllah. And don't worry, everyone goofed up in some parts. One of the smartest people I know messed up and thinks he's only gonna get 33. :3

I'm writing up #7 now, it'll be uploaded in a bit. ;_; I fell asleep, and I practiced some P3 maths. Sorry.
 
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