Question

Assertion (A): When an object or body is moving at a constant velocity, with no changes in speed or direction, it is dynamic equilibrium.
Reason (R): A cyclist in motion or the body position maintained by a sprinter on the track while running are examples of dynamic equilibrium.

• A. Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of the Assertion (A).
• B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
• C. Assertion (A) is true, but Reason (R) is false.
• D. Assertion (A) is false, but Reason (R) is true.

Hint:

Remember: Equilibrium = Net Force is Zero. If the body is still, it's Static. If the body is moving at a steady speed in a straight line, it's Dynamic.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:  
Equilibrium in biomechanics is divided into two types: Static (at rest) and Dynamic (in motion). Dynamic equilibrium occurs when all forces acting on a moving body are balanced, resulting in constant velocity. 

Step 2: Detailed Explanation: 
 

1. Assertion (A): The definition of dynamic equilibrium is the state where a body moves with uniform velocity (no acceleration). 
    
2. Reason (R): A cyclist or sprinter maintaining a steady state of motion is successfully balancing the driving forces against resistive forces (such as air resistance and friction). 
    
3. Conclusion: Since the examples in Reason (R) perfectly illustrate the definition provided in Assertion (A), Reason (R) is the correct explanation for Assertion (A). 
    

Step 3: Final Answer: 
Both statements are true, and Reason (R) explains Assertion (A).