A system of masses rotating in different parallel planes is in dynamic balance if-
- A. Resultant force is zero
- B. resultant couple is zero
- C. resultant force in numerically equal to resultant couple
- D. resultant force and the resultant couple both are equal to zero
Answer: D. resultant force and the resultant couple both are equal to zero
Explanation: Dynamic balance requires both force polygon closure (static balance) and couple polygon closure.