Topic: Engineering Mechanics
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. (Angle ZX makes 45 deg with horizontal/vertical, ZY makes 60 deg).
- A. 14 kg
- B. 20 kg
- C. 10 kg
- D. 5 kg
Answer: B. 20 kg
Explanation: Applying Lami's Theorem at node Z: Tension B / sin(180 - 45) = Load A / sin(45 + 60). Therefore, B / sin(135) = 27.3 / sin(105). B = 27.3 * sin(45) / sin(105) = 27.3 * 0.707 / 0.9659 = 19.98 kg, which rounds to 20 kg.