Question

The angle between two straight bars is ${30}^o.$

For what minimum angle any of the bars must be rotated about the common point to make the angle between them as $0^o.$

• A. Rotation of bar A by ${30}^o$ in clockwise direction.
• B. Rotation of bar A by ${30}^o$ in anticlockwise direction.
• C. Rotation of bar B by ${30}^o$ in clockwise direction.
• D. Rotation of bar B by ${30}^o$ in anticlockwise direction.

Answer 1

Answer: (A), (D)

Rotation of bar B by ${30}^o$ in anticlockwise direction.

To make the angle between the bars as $0^o,$ their position must coincide, i.e., they must lie upon each other.

Such positions are possible either by rotation of bar A by ${30}^o$ in the clockwise direction or by rotation of bar B by ${30}^o$ in the anticlockwise direction.
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