- #1
afrocod
- 31
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A ring of weight 2N is threaded on to a string whose ends are fixed to two points A and B in a horizontal line. The ring is pulled aside by a horizontal force P Newton parallel to AB. When the ring is in equilibrium the two sections of the string are inclined to the vertical at angles of 40° and 20°. Find the two possible values of P.
The sum of all the forces = 0 and because it says the 2 possible values of P, I'm guessing the Cosine rule is relevant.
I tried to separate out horizontal and perpendicular vectors like : X = P + T1Sin20 - T2sin40 = 0 and Y = -2 + T1Cos20 + T2Cos40 = 0. and it doesn't work out. I'm also thinking the tension in both segments = 2N
I've followed lots of different tactics out but it just never comes out right and it's draining my will to live. I'm almost certain the problem is, I'm just not able to see what are the relevant forces in the problem, I'm having a hard time making a mental model of it.
Also I'm self studying this material, so I've got no one else to turn to. Please help me out.
The sum of all the forces = 0 and because it says the 2 possible values of P, I'm guessing the Cosine rule is relevant.
I tried to separate out horizontal and perpendicular vectors like : X = P + T1Sin20 - T2sin40 = 0 and Y = -2 + T1Cos20 + T2Cos40 = 0. and it doesn't work out. I'm also thinking the tension in both segments = 2N
I've followed lots of different tactics out but it just never comes out right and it's draining my will to live. I'm almost certain the problem is, I'm just not able to see what are the relevant forces in the problem, I'm having a hard time making a mental model of it.
Also I'm self studying this material, so I've got no one else to turn to. Please help me out.