An open vessel of water is accelerated up an inclined plane. The free water surface will A. be horizontal B. make an angle in direction of inclination of inclined plane C. make an angle in opposite direction to inclination of inclined plane D. any one of above is possible

The correct answer is: The free water surface will make an angle in the direction of inclination of the inclined plane.

When an open vessel of water is accelerated up an inclined plane, the water will experience a force in the direction of the acceleration. This force will cause the water to accelerate up the inclined plane. The free water surface will therefore make an angle in the direction of inclination of the inclined plane.

The other options are incorrect because:

• Option A is incorrect because the free water surface will not be horizontal.
• Option B is incorrect because the free water surface will not make an angle in the opposite direction to the inclination of the inclined plane.
• Option C is incorrect because it is not the only possible answer.