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just removed the space after "Math.sin((6.28/a. " & then try..
this should work..
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solution::
using i-j convention of vectors
velocity of boy (v1) = 4i
velocity of rain (V) = x i + y j
(V1rel) velocity of wind with respect to boy = (x i + y j) - 4 i = (x-4)i + y j
but wind blows from north, so (x-4)i = 0
=> x = 4.
new velocity of boy (v2) = 7i
new relative velocity (V2rel) = (4-7)i + y j = -3i + yj
since, now the relative velocity is in north-east direction, so, root((9+y^2)) cos 45 = -3 -->(taken the horizontal component in this step)
solving, you'll get y = 3
=>magnitude velocity of wind is squareroot(16 + 9) = 5 kmph
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hey, try reading the NCERT or any other refernce book, it would definitely be explained there(in a better way)...
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tension & electromagnetic force are two entirely different forces. tension is mostly in string where there is some kind of contact whereas electromagnetic forces are the force developed due to motion of charges (independent of contact of bodies)....
so, electromagnetic forces cannot be considered as tension...
i hope this helps....
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i'd say its quite necessary to learn all the reactions coz' you'll be using them while doin' the questions...
moreover, if you want to learn them then do write them.
like when you doin a particular chapter then 1st write the reactions by seeing them & try to memorise them,
when the 2nd time you'll read the chapter, say after a week, then, try to write the reactions without seeing them....
i hope this helps....
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i just made the mistake in takin 0.072 M instead of 0.074 M.....
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To do this without differentiation, try to apply A.M. G.M. .... btw, wat's the ans. ??
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solution:: moles of Cl- prepared = 0.072/2 = 0.036 moles 1 mole BaCl2.2H2O gives 2 moles of Cl- => 1 moles of Cl- will be given by 1/2 mole of BaCl2.2H2O => 0.036 moles of Cl- will be given by 0.036/2 = 0.018 moles of BaCl2.2H2O => mass of BaCl2.2H2O required = 244 * 0.018 = 4.392g (ans.)
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see, if you try to do this question in ground frame then it would become very difficult but when you do the question in frame of reference of the balloon then the question becomes much easier but a little visualisation is required....
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see, the stones are just dropped from the balloon, so, relative to the balloon(i.e. in frame of reference of the balloon or considering the motion when the balloon becomes stationary) their initial velocity becomes zero. [try to visualise it]....
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in short, 3 conditions are to be satisfied for the roots to be >1
1) D>0
2) -b/2a > 1
3) a * f(1) > 0
f(x)=(a+1)x^2 - 3ax + 4a =0
using the equation satisfy the above 3 conditions & you'll get the ans.
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the ans. is 52m
consider the motion in the frame of reference of the balloon.
=> the acceleration of the stones become 10.4 m/s^2
when the stones are dropped their initial velocities are zero
we have to find the distance between the stones after 1.5 sec(i.e after the 1st stone is dropped) & after 3.5 (i.e. 2 + 1.5 seconds after the 2nd stone is dropped)
S(1) = (1/2) * 10.4 * (1.5)^2
S(2) = (1/2) * 10.4 * (3.5)^2
distance (d) between the stones = S(2) - S(1)
d = 5.2 * [ 12.25 - 2.25 ]
d = 52 m (ans.)
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i also think the ans. is circle
see, |x-z| gives the distance of x from z & |z-w| gives the distance of x from w. since, |x-z|/|x-w| = k where k is not equal to 1, so this would form a circle....
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see man, this isn't that tough but it requires a little logic....
Q)prove that 1111................ is not a prime number
<----91 digits----->
A) 1111......(91 digits)
if you'll observe, then you'll see that 91 is divisible by 13 or 7.
so, if we take 11111.....(13 digits) or 111....(7 digits) then it would definitely divide 1111......(91 digits) [try to visulalise it]
=> 1111......(91 digits) is divisible by 1111...(13 digits) and 1111111(7 digits) which proves that 1111......(91 digits) is not a prime number....
cheers!
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