A buoyancy conundrum urgent! Don t plagiarize from the Internet, have a detailed analysis process

a） （b） （c）

In Figure (a), the block is subjected to a tensile force f1, gravity and buoyancy

In Figure (b), the thin line is cut off, the wooden block is in a floating state, and the volume of the drained water is V In Figure (c), after cutting off the part that is exposed to the water surface, the wooden block is still floating, and then again.

When the pressure of f2 1 n is applied, there is still part of the volume exposed to the water surface Known: f1 = 2n, f2 = 1n, v 20cm3—2 10—5m3 Find: water. Solution According to the three diagrams, the wooden blocks are all stationary, and the force equilibrium process is listed separately.

Substitute the quantities in the formula, where v row refers to the volume of drained water in Figure (b), into numerical facts, and use SI units (omitted) in the process

Water v— wood v

Water V Row — Wood V

Water V Row - Wood V Row) Water 2 10—5

About v and v, get: water

Answer The density of wooden blocks is.

You have to choose me! Feel free to keep asking!

Solution: 1. When f is a negative value, it means that the f force acts on the lower bottom surface and supports the object to the water surface.

As can be seen from the graph, when the f-force is greater, h will be smaller.

When f a=400n, h=0, it means that the bottom surface of the object has reached the surface of the water.

At this time, the object is not affected by buoyancy, but only by the f-force and its own gravity.

Again: The title tells us that the workpiece is slowly pressed into the water, and it can be considered that the object is always in equilibrium during the motion.

So at this time, there is: f mg, i.e., the value of a is the gravitational force of the workpiece.

2. In the third question, it is indeed f floating mg+f

But as before, the workpiece is slowly pressed into the water.

At this point, the force is still balanced.

If you have any questions about this question, please ask!

According to the prompts in the question, when f is negative, it means that its direction is opposite to the original direction, that is, the direction of f is upward, that is, the force f pulls the object upwards (at this time the object leaves the oil surface). At this time, the object is stationary, and the two forces are balanced in the vertical direction, that is, the tensile force f is balanced with the gravitational force g, so that a represents both the tensile force f and the gravitational force g of the object

You are digging into the horns, and the question is about the state corresponding to point C, that is, only point C is considered, and nothing else is considered. You imagine that the object is stationary at point C. Buoyancy Gravity plus pressure is right, and it's very useful for solving this problem.

Welcome to it! Thank you!