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Consider the two statements related to c...

Consider the two statements related to circular motion in usual notations
A. In uniform circular motion `vec(omega), vec(v) and vec(a )` are always mutually perpendicular
B. In non-uniform circular motion `vec(omega) ,vec(v) and vec(a) ` are always mutually perpendicular

A

both A and B are true

B

both A and B are false

C

A is true but B is false

D

A is false but B is true

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the two statements related to circular motion and determine their validity. ### Step 1: Analyze Statement A **Statement A:** In uniform circular motion, \(\vec{\omega}\), \(\vec{v}\), and \(\vec{a}\) are always mutually perpendicular. 1. **Understanding Uniform Circular Motion:** - In uniform circular motion, a particle moves in a circular path with a constant speed. - The velocity vector \(\vec{v}\) is always tangent to the circular path. - The acceleration vector \(\vec{a}\) in uniform circular motion is the centripetal acceleration, which points towards the center of the circle. 2. **Relationship Between Vectors:** - The velocity \(\vec{v}\) is tangent to the circle, and the centripetal acceleration \(\vec{a}\) is directed towards the center, making them perpendicular. - The angular velocity vector \(\vec{\omega}\) is directed along the axis of rotation (perpendicular to the plane of motion). In a right-handed coordinate system, it points out of the plane of the circle. - Therefore, \(\vec{\omega}\) is also perpendicular to both \(\vec{v}\) and \(\vec{a}\). **Conclusion for Statement A:** True. In uniform circular motion, \(\vec{\omega}\), \(\vec{v}\), and \(\vec{a}\) are mutually perpendicular. ### Step 2: Analyze Statement B **Statement B:** In non-uniform circular motion, \(\vec{\omega}\), \(\vec{v}\), and \(\vec{a}\) are always mutually perpendicular. 1. **Understanding Non-Uniform Circular Motion:** - In non-uniform circular motion, a particle moves in a circular path with a variable speed. - The velocity vector \(\vec{v}\) is still tangent to the circular path. - There are two components of acceleration: - Centripetal acceleration \(\vec{a}_c\) directed towards the center of the circle. - Tangential acceleration \(\vec{a}_t\) which is directed along the tangent to the path (in the direction of increasing speed). 2. **Relationship Between Vectors:** - The net acceleration \(\vec{a}\) is the vector sum of \(\vec{a}_c\) and \(\vec{a}_t\). This net acceleration will not be perpendicular to the velocity vector \(\vec{v}\) because it has a tangential component. - While \(\vec{\omega}\) remains perpendicular to the plane of motion, the presence of the tangential acceleration means that \(\vec{a}\) is not perpendicular to \(\vec{v}\). **Conclusion for Statement B:** False. In non-uniform circular motion, \(\vec{a}\) is not perpendicular to \(\vec{v}\), hence \(\vec{\omega}\), \(\vec{v}\), and \(\vec{a}\) are not mutually perpendicular. ### Final Conclusion - **Statement A:** True - **Statement B:** False Thus, the correct answer is that Statement A is true, and Statement B is false. ---
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