Physics
Assertion (A): When a beam is in static equilibrium, the sum of clockwise moments is equal to the sum of anticlockwise moments.
Reason (R): According to the principle of moments for a body in equilibrium, the sum of moments acting in one direction must be equal to the sum of moments in opposite direction.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true and R is not the correct explanation of A.
- assertion is false but reason is true.
- assertion is true but reason is false.
Answer
Both A and R are true and R is the correct explanation of A.
Explanation
Assertion (A) is true because when the sum of the clockwise moments acting on the beam is equal to the sum of the anticlockwise moments, their resultant sum is zero and the beam has no rotational motion. Hence, it is in static equilibrium.
Reason (R) is true because it provides a logical explanation for Assertion (A), stating the principle of moments for a body in equilibrium, which aligns with the definition of static equilibrium.
Related Questions
Assertion (A): A heavier object placed at a far distance from the pivot point will have the same moment as a lighter object placed close to the pivot point.
Reason (R): The moment of force is determined by the magnitude of the force along with its distance from the pivot point.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true and R is not the correct explanation of A.
- assertion is false but reason is true.
- assertion is true but reason is false.
Assertion (A): The centre of gravity of an irregularly-shaped object always lies at its geometric centre.
Reason (R): The centre of gravity depends on the distribution of mass within an object.
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- Both A and R are true and R is not the correct explanation of A.
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Assertion (A): A crack in a glass vessel often shines like a mirror.
Reason (R): It shines due to the refraction of light.
- Both A and R are true.
- Both A and R are false.
- A is false but R is true.
- A is true but R is false.
Assertion (A): The focal length of a lens does not change when red light is replaced by blue light.
Reason (R): The focal length of a lens depends on the refractive index of material of lens.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true and R is not the correct explanation of A.
- assertion is false but reason is true.
- assertion is true but reason is false.