Author Topic: All Mechanics DOUBTS HERE!!!  (Read 85125 times)

Offline Saladin

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Re: All Mechanics DOUBTS HERE!!!
« Reply #180 on: May 23, 2010, 03:16:06 pm »
The i co-ordinates have to be the same in order for something to be due south of something.

Thus, we have to see, how long it takes for the i co-ordinates to become equal.

Thus, we got that the speed is 2i-3.5j

So, the i co-ordinate of A is 7.

Thus,

\frac{7}{2}=3.5

The total time to get to the point (0,0) is 7 seconds, 4+3.

Thus you simply add the new value to 7. And you get the answer: 10.5

Offline perrychan527

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Re: All Mechanics DOUBTS HERE!!!
« Reply #181 on: May 23, 2010, 05:11:52 pm »
The i co-ordinates have to be the same in order for something to be due south of something.

Thus, we have to see, how long it takes for the i co-ordinates to become equal.

Thus, we got that the speed is 2i-3.5j

So, the i co-ordinate of A is 7.

Thus,

\frac{7}{2}=3.5

The total time to get to the point (0,0) is 7 seconds, 4+3.

Thus you simply add the new value to 7. And you get the answer: 10.5
Thx, i got it. ;) ;) ;)

Offline raimunts

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Re: All Mechanics DOUBTS HERE!!!
« Reply #182 on: May 23, 2010, 05:35:17 pm »
What is the value of acceleration due to gravity, g in m1?
And do we have to write answeres which involve g in terms of g, or in decimals? please help

Offline astarmathsandphysics

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Re: All Mechanics DOUBTS HERE!!!
« Reply #183 on: May 23, 2010, 06:01:43 pm »
9.81 or 9.8 or 10 if I am asked to find a numerrical value
I always use 9.8 but you may be told to use a value in the question
In terms of g is always best

Offline 7ooD

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Re: All Mechanics DOUBTS HERE!!!
« Reply #184 on: May 23, 2010, 06:12:51 pm »
in m1 it is always 9.8
pimpin ain't dead it just moved to the web



Offline zabady

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Re: All Mechanics DOUBTS HERE!!!
« Reply #185 on: May 23, 2010, 08:55:04 pm »
plzzz someone question 6 a b c for they said R is parallel to vector (i-2j) i understand by parallel that it means R=K * (i-2j).....,and for b and c i cant get them

Offline astarmathsandphysics

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Re: All Mechanics DOUBTS HERE!!!
« Reply #186 on: May 23, 2010, 08:57:33 pm »
6abc what year and board

Offline Saladin

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Re: All Mechanics DOUBTS HERE!!!
« Reply #187 on: May 23, 2010, 09:00:07 pm »
plzzz someone question 6 a b c for they said R is parallel to vector (i-2j) i understand by parallel that it means R=K * (i-2j).....,and for b and c i cant get them

which year?

Offline zabady

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Re: All Mechanics DOUBTS HERE!!!
« Reply #188 on: May 23, 2010, 09:01:23 pm »
looool sry 2009 january....m1 edexcel the linkk for paper http://freeexampapers.com/FreeExamPapers.com_.php?__lo=QSBMZXZlbC9NYXRocy9FZGV4Y2VsL00xL00xIDIwMDktMDEucGRm and the ms http://freeexampapers.com/FreeExamPapers.com_.php?__lo=QSBMZXZlbC9NYXRocy9FZGV4Y2VsL00xL00xIDIwMDktMDEgTVMucGRm

question says

6. Two forces, (4i – 5j) N and (pi + qj) N, act on a particle P of mass m kg. The resultant
of the two forces is R. Given that R acts in a direction which is parallel to the
vector (i – 2j),
(a) find the angle between R and the vector j,
(3)
(b) show that 2p + q + 3 = 0.

ms says

tan? = 2
1
?? = 63.4
angle is 153.4


(4 + p)i + (q ? 5)j
(q ? 5) = ?2(4 + p)
2 p + q + 3 = 0 *
« Last Edit: May 23, 2010, 09:06:53 pm by zabady »

Offline Saladin

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Re: All Mechanics DOUBTS HERE!!!
« Reply #189 on: May 23, 2010, 09:02:40 pm »
looool sry 2009 january....m1 edexcel

sir, i need to go to sleep. I have been helping all day.....

Pls take this one.

Offline astarmathsandphysics

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Re: All Mechanics DOUBTS HERE!!!
« Reply #190 on: May 23, 2010, 09:07:28 pm »
will do

Offline zabady

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Re: All Mechanics DOUBTS HERE!!!
« Reply #191 on: May 23, 2010, 09:10:35 pm »
thanks and please explain how you did part a i don't understand why they took i-2j when it is supposed to be parallel not equal

Offline astarmathsandphysics

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Re: All Mechanics DOUBTS HERE!!!
« Reply #192 on: May 23, 2010, 09:16:32 pm »
Two forces, (4i – 5j) N and (pi + qj) N, act on a particle P of mass m kg. The resultant
of the two forces is R. Given that R acts in a direction which is parallel to the
vector (i – 2j),
(a) find the angle between R and the vector j,
(3)
(b) show that 2p + q + 3 = 0.
a)cos x=j.(i-2j)/|i||i-2j|=1aqrt(5) so x=cos^-1 1/sqrt5

4i-5j+pi+qj=k(i-2j)
4+p=k   (3)
-5+q=-2k (4)
(3)*2+(4) gives2p + q + 3 = 0

Offline raimunts

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Re: All Mechanics DOUBTS HERE!!!
« Reply #193 on: May 23, 2010, 09:20:35 pm »
Hey, can someone please suggest 2 or 3 of the MOST DIFFICULT solomon paper questions of each chapter of M1? Please help!

Offline zabady

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Re: All Mechanics DOUBTS HERE!!!
« Reply #194 on: May 23, 2010, 09:22:54 pm »
i dnt get part a at all