Question

Spreading forces over surfaces I. Block that floats when released A cubical block is observed to float in a beaker of water. The block is then held near the center of the beaker as shown and released. A. Describe the motion of the block after it is released. Lab section B. Draw a free-body diagram for the block at the instant that it is Free-body diagram for block at instant it is released released. Rather than drawing a single force by the water on the block, show the forces that the water exerts on each of the six surfaces of the block. C. Rank the magnitudes of the vertical forces in your free-body diagram. If you cannot completely rank the forces, explain why you cannot. Chec k that your answer is consistent with the motion of the block: Check that your answer is consistent with how pressure varies with depth in a liquid D. Did you draw any forces acting downward on the top surface of the block? Explain. In the box at right, draw a vector to represent the vector sum of the forces exerted on the block by the surrounding water. 1. Is this vector equal to the net force on the block? (Recall that the net force E. is defined as the vector sum of all forces acting on an object.) 2. Is the magnitude of the sum of the forces exerted on the block by the water greater than, less than, or equal to the weight of the block? Explain.

Answer 1

It will move upward linearly B_1, B_2 from It will move upward linearly. Forces exerted By water only. Vertical forces are B_4, B_3 B_3 > B_4 Bottom surfaces is more depth than upper, hence force of Buoyancy is more at Bottom surface. Net force is in upward direction hence block move upward \r\n pressure increases at depth p alpha d P = Pressure d = depth Yes, force B_u, It is the downward force exerted by upper water column on block. Weight of object (mg) will also Act in downward direction.