Qualification > Queries
ANY DOUBTS HERE!!!
Ghost Of Highbury:
A lamp is supported in equilibrium by 2 chains fixed to 2 points A and B at the same level.
i) The lengths of the chain are 0.3m and 0.4m and the distance between A and B is 0.5m. Given the tension in the longer chain is 36N, by resolving horizontally , find the tension in the shorter chain.
ii) By resolving vertically , find the mass of the lamp.
Please explain with A DIAGRAM!, thanks a lot! :D
halosh92:
--- Quote from: nid404 on May 28, 2010, 11:44:55 am ---it's falling vertically down...so you use the vertical component
x when weight is F+3.8N =17.8-14.2=3.6cm=0.036m
x when weight is 3.8N=16.3-14.2=2.1cm=0.021m
2 epe= 1/2 kx2 = 1/2 X 1.8 X 10^-2 X (change in x2)
=1/2 X 1.8 X10^-2 X (0.0362-0.0212)
=0.077 J
--- End quote ---
the answer am getting is 0.00000769
and for the extension why arent we taking only this extension:
x when weight is 3.8N=16.3-14.2=2.1cm=0.021m
as this is wat they only asked for...
nid404:
Yup so here you go.
You the the angle between the two chains is 90. 0.32+ 0.42= 0.52 yup?
now find angles a and b
tan a= 0.4/0.3=53.13
b= 180-90-53.13=36.87
now sina/36 = sinb/ T is the shorter chain
T=27N in the shorter chain
Now resolving forces vertically
36sin36.87+27sin53.13= mg
0.6X36+ 0.8X27=mg
mg=45
m=4.5 kg
nid404:
--- Quote from: halosh92 on May 28, 2010, 12:29:02 pm ---the answer am getting is 0.00000769
and for the extension why arent we taking only this extension:
x when weight is 3.8N=16.3-14.2=2.1cm=0.021m
as this is wat they only asked for...
--- End quote ---
It says For the extension of the spring from a length of 16.3 cm to a length of 17.8 cm ... :-\
Ghost Of Highbury:
--- Quote from: nid404 on May 28, 2010, 12:36:02 pm ---Yup so here you go.
You the the angle between the two chains is 90. 0.32+ 0.42= 0.52 yup?
now find angles a and b
tan a= 0.4/0.3=53.13
b= 180-90-53.13=36.87
now sina/36 = sinb/ T is the shorter chain
T=27N in the shorter chain
Now resolving forces vertically
36sin36.87+27sin53.13= mg
0.6X36+ 0.8X27=mg
mg=45
m=4.5 kg
--- End quote ---
ok sry, i didnt put the q rite, it says by resolving horizontally show that the T in the shorter chain is 48N! not 27N
plus, the mass is 6kg :-/
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