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Question-58668




Question Number 58668 by ajfour last updated on 27/Apr/19
Commented by ajfour last updated on 27/Apr/19
If Cars Blue and Pink start off at A  only to meet again in the closed   path ABC both at zero speed  simultaneously. Knowing that at  the corners the speed≤10km/h  and if max acceleration of each car   is (20km/h)/s then find the shortest  time in which they can meet.  Take a=3km , b=5km, c=4km.
$$\mathrm{If}\:\mathrm{Cars}\:\mathrm{Blue}\:\mathrm{and}\:\mathrm{Pink}\:\mathrm{start}\:\mathrm{off}\:\mathrm{at}\:\mathrm{A} \\ $$$$\mathrm{only}\:\mathrm{to}\:\mathrm{meet}\:\mathrm{again}\:\mathrm{in}\:\mathrm{the}\:\mathrm{closed}\: \\ $$$$\mathrm{path}\:\mathrm{ABC}\:\mathrm{both}\:\mathrm{at}\:\mathrm{zero}\:\mathrm{speed} \\ $$$$\mathrm{simultaneously}.\:\mathrm{Knowing}\:\mathrm{that}\:\mathrm{at} \\ $$$$\mathrm{the}\:\mathrm{corners}\:\mathrm{the}\:\mathrm{speed}\leqslant\mathrm{10km}/\mathrm{h} \\ $$$$\mathrm{and}\:\mathrm{if}\:\mathrm{max}\:\mathrm{acceleration}\:\mathrm{of}\:\mathrm{each}\:\mathrm{car}\: \\ $$$$\mathrm{is}\:\left(\mathrm{20km}/\mathrm{h}\right)/\mathrm{s}\:\mathrm{then}\:\mathrm{find}\:\mathrm{the}\:\mathrm{shortest} \\ $$$$\mathrm{time}\:\mathrm{in}\:\mathrm{which}\:\mathrm{they}\:\mathrm{can}\:\mathrm{meet}. \\ $$$$\mathrm{Take}\:\mathrm{a}=\mathrm{3km}\:,\:\mathrm{b}=\mathrm{5km},\:\mathrm{c}=\mathrm{4km}. \\ $$
Commented by MJS last updated on 27/Apr/19
sorry but a+c=b ⇒ B lies on b?!
$$\mathrm{sorry}\:\mathrm{but}\:{a}+{c}={b}\:\Rightarrow\:{B}\:\mathrm{lies}\:\mathrm{on}\:{b}?! \\ $$
Commented by ajfour last updated on 27/Apr/19
yes, sir; i dint think well, sorry!
$$\mathrm{yes},\:\mathrm{sir};\:\mathrm{i}\:\mathrm{dint}\:\mathrm{think}\:\mathrm{well},\:\mathrm{sorry}! \\ $$
Commented by MJS last updated on 27/Apr/19
...there could have been curves in the roads...
$$…\mathrm{there}\:\mathrm{could}\:\mathrm{have}\:\mathrm{been}\:\mathrm{curves}\:\mathrm{in}\:\mathrm{the}\:\mathrm{roads}… \\ $$

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