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=267.513NVertical Force BalanceT1sin(45∘)+T2sin(60∘)=WHorizontal Force Balance at ZT1cos(45∘)=T2cos(60∘)Step 3: Use Trig Valuessin(45∘)=cos(45∘)=22≈0.7071sin(60∘)=23≈0.8660,cos(60∘)=0.5From Equation (2):T1⋅0.7071=T2⋅0.5=>T1=0.70710.5T2=>T1≈0.7071T2Step 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=1.3660267.513≈195.85NStep 5: Tension in ZY equals Weight of BT2=WB=mB⋅g=>mB=9.81T2=9.81195.85≈20kg(rounded to nearest integer)(3)