Assertion (A): Two concentric helical springs used to provide greater ...
**Explanation:**
**Assertion (A): Two concentric helical springs used to provide greater spring force are wound in opposite directions.**
This assertion is true. When two concentric helical springs are wound in opposite directions, they are called double-wound springs. These springs are commonly used in applications where a higher spring force is required. The winding in opposite directions allows the springs to work together, effectively increasing the overall spring force.
**Reason (R): The winding in opposite directions in the case of helical springs prevents buckling.**
This reason is false. The winding in opposite directions in the case of helical springs does not prevent buckling. Buckling is a phenomenon where a slender structure, such as a spring, fails due to compressive loads. It occurs when the critical buckling load is exceeded. The winding direction of the spring does not have a direct impact on its buckling behavior.
**Explanation:**
The assertion states that two concentric helical springs used to provide greater spring force are wound in opposite directions. This is true because when two springs are wound in opposite directions, they work together to provide a higher overall spring force. The opposite winding direction allows the springs to exert forces in the same direction, effectively doubling the spring force.
The reason states that the winding in opposite directions in the case of helical springs prevents buckling. This is false because the winding direction of the spring does not have a direct impact on its buckling behavior. Buckling is primarily influenced by the geometry and material properties of the spring, such as its length, diameter, and modulus of elasticity. The winding direction does not change these fundamental properties and therefore does not prevent buckling.
In conclusion, the assertion is true as two concentric helical springs are indeed wound in opposite directions to provide greater spring force. However, the reason is false as the winding direction does not prevent buckling in helical springs. Therefore, option C is the correct answer.
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