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A small ring Z carries vertical load A of mass 27.3 kg by two strings ZX and ZY. String ZY carries a load B at its free end through a frictionless pul
Question

A small ring Z carries vertical load A of mass 27.3 kg by two strings ZX and ZY. String ZY carries a load B at its free end through a frictionless pulley. Find the value of B (rounded to nearest integer), if the string is stable at the configuration shown in fig.

A.

14 kg

B.

20 kg

C.

10 kg

D.

5 kg

Correct option is B

Let:T1=tension in ZX (angle 45)T2=tension in ZY (angle 60)W=mg=27.3×9.81=267.513 NVertical Force BalanceT1sin(45)+T2sin(60)=WHorizontal Force Balance at ZT1cos(45)=T2cos(60)Step 3: Use Trig Valuessin(45)=cos(45)=220.7071sin(60)=320.8660,cos(60)=0.5From Equation (2):T10.7071=T20.5=>T1=0.50.7071T2=>T10.7071T2Step 4: Plug into Equation (1)0.7071T1+0.8660T2=267.5130.7071(0.7071T2)+0.8660T2=267.5130.5T2+0.8660T2=267.5131.3660T2=267.513=>T2=267.5131.3660195.85 NStep 5: Tension in ZY equals Weight of BT2=WB=mBg=>mB=T29.81=195.859.8120 kg(rounded to nearest integer)(3)\textbf{Let}: \\T_1 = \text{tension in ZX (angle } 45^\circ) \\T_2 = \text{tension in ZY (angle } 60^\circ) \\W = mg = 27.3 \times 9.81 = 267.513\, \text{N} \\\\\textbf{Vertical Force Balance} \\T_1 \sin(45^\circ) + T_2 \sin(60^\circ) = W \\\\\textbf{Horizontal Force Balance at Z} \\T_1 \cos(45^\circ) = T_2 \cos(60^\circ) \\\\\textbf{Step 3: Use Trig Values} \\\sin(45^\circ) = \cos(45^\circ) = \frac{\sqrt{2}}{2} \approx 0.7071 \\\sin(60^\circ) = \frac{\sqrt{3}}{2} \approx 0.8660, \quad \cos(60^\circ) = 0.5 \\\\\text{From Equation (2):} \\T_1 \cdot 0.7071 = T_2 \cdot 0.5 \Rightarrow T_1 = \frac{0.5}{0.7071} T_2 \Rightarrow T_1 \approx 0.7071 T_2 \tag{3} \\\\\textbf{Step 4: Plug into Equation (1)} \\0.7071 T_1 + 0.8660 T_2 = 267.513 \\0.7071 (0.7071 T_2) + 0.8660 T_2 = 267.513 \\0.5 T_2 + 0.8660 T_2 = 267.513 \\1.3660 T_2 = 267.513 \Rightarrow T_2 = \frac{267.513}{1.3660} \approx 195.85\, \text{N} \\\\\textbf{Step 5: Tension in ZY equals Weight of B} \\T_2 = W_B = m_B \cdot g \Rightarrow m_B = \frac{T_2}{9.81} = \frac{195.85}{9.81} \approx \boxed{20\, \text{kg}} \quad \text{(rounded to nearest integer)}​​

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