dazedconfused
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hi, could i have some help pleaseeee, i am so confused
7. In this question, the unit vector i is horizontal and the unit vector j is vertically upwards. All forces are in newtons.

A small, heavy box is suspended in mid-air and is held in equilibrium by the tension in a light inextensible string and a horizontal force, as shown in the diagram.











The tension in the string is T1, where T1 = 30i + 49j. The horizontal force is F1, where F1 = pi.

(i) Write down the value of p and show that the mass of the box is 5 kg. [3]

(ii) Calculate the magnitude of T1 and the angle that T1 makes with the horizontal.
[3]
Another force F2 = 48i – 87j is now applied to the box. The force F1 still acts and the box is still in equilibrium.

(iii) The new tension in the string is T2 = ai + bj. Calculate the values of a and b. [2]
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dazedconfused
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Muttley79
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(Original post by dazedconfused)
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Have you tried equating i components, then j components?
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dazedconfused
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(Original post by Muttley79)
Have you tried equating i components, then j components?
for part i??
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Muttley79
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(Original post by dazedconfused)
for part i??
Yes
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dazedconfused
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(Original post by Muttley79)
Yes
i feel really annoying but could you please explain by what you mean when you say equating the i and j components?? i would appereciate it alot
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Muttley79
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(Original post by dazedconfused)
i feel really annoying but could you please explain by what you mean when you say equating the i and j components?? i would appereciate it alot
The tension in the string is T1, where T1 = 30i + 49j. The horizontal force is F1, where F1 = pi.

I can't do it for you, it's against the rules, but put the i part of T1 = to the i part of F1.

Then the j component must equal what other force?
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dazedconfused
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(Original post by Muttley79)
The tension in the string is T1, where T1 = 30i + 49j. The horizontal force is F1, where F1 = pi.

I can't do it for you, it's against the rules, but put the i part of T1 = to the i part of F1.

Then the j component must equal what other force?
OHHHH then j is vertical force which is the weight
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dazedconfused
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(Original post by dazedconfused)
OHHHH then j is vertical force which is the mass
how had i not seen this omg thank you, i've actually done the rest of the questions, thank youuuu for your help
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stephja2004
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(Original post by dazedconfused)
how had i not seen this omg thank you, i've actually done the rest of the questions, thank youuuu for your help
Pleaseeeeee please please can someone help me with this question?? im so confused
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davros
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(Original post by stephja2004)
Pleaseeeeee please please can someone help me with this question?? im so confused
This thread is a year old, but have you followed the hints given above to answer the first part?
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