How to calculate support

1. The density of mercury is 13.6g/cm ^ 3, and the density of iron block is 7.9g/cm ^ 3. If the quantity of mercury is enough, the iron block will have v row = 13.6 / 7.9 * V immersed in mercury, but in fact, the depth of mercury is only 3cm, so the iron block still has a certain pressure on the bottom of the container.
the actual size of floating force on the iron block is: F floating = density of mercury * g * (3cm * 8cm * 8cm) = 26n

2.

There is no specific formula for supporting force. Sometimes supporting force = gravity or = friction

when expounding the concept of supporting force, it is always said that one object has supporting force for another, then the latter is the stressed object, and the point of action should be marked on the stressed surface. For example, if a wooden block is placed on the horizontal desktop and is supported by the desktop, the point of action of the supporting force is marked on the center of gravity of the wooden block

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extended data:

I. nature of force:

1. Materiality: force is the effect of object (matter, mass) on object (matter, mass). When an object is under the action of force, another object must exert this effect on it. Force cannot exist independently without object

3. Vectoriality: force is a vector, which has both magnitude and direction

4. Simultaneity: the force proced and disappeared at the same time

Independence: the effect of one force does not affect the effect of another

According to the nature of force, it can be divided into gravity, universal gravitation, elastic force, friction force, molecular force, electromagnetic force, nuclear force, etc. Gravity does not point to the center of the earth

2. According to the effect of force, it can be divided into tension, tension, pressure, supporting force, power, resistance, centripetal force, restoring force, etc< According to the research object, it can be divided into external force and internal force

4. According to the action mode of force, it can be divided into non-contact force (such as gravitational force, electromagnetic force, etc.) and contact force

5. Four basic interactions (forces): gravitational interaction, electromagnetic interaction, strong interaction and weak interaction

3. The weight only increases the gravitational potential energy, as long as the height change is calculated
two right triangles can be made from two positions AB, and the bottom length of the two triangles can be expressed by height H. the difference between them is 2, and the height h can be solved. Then the oblique side length of the two triangles can be calculated respectively, and the difference is the change of height.

4. Supporting force is the force of one object on the contact surface of another. The supporting force can be represented by the symbol "n" Normal force)
object exerting force: the object exerting force (the earth) the object under force: the object under force note: the object exerting force is also the object under force (because the force between objects is mutual) and has mutual characteristics
supporting force is not gravity
gravity is vertical downward
supporting force is the force given to an object by the supporting surface

5. It is equal to the downward force perpendicular to the ground. If the ground is horizontal, it is equal to gravity. If it is inclined, it is necessary to calculate the force perpendicular to the ground by orthogonal decomposition or other methods

6. Perpendicular to the slope downward

7. The supporting force in junior high school physics, according to the motion state of the object, is calculated indirectly after the force analysis and according to the balance of the two forces
△ the supporting force in high school physics, according to the motion state of objects, after force analysis of multiple objects, one is: according to the balance of two forces, the supporting force is indirectly calculated; Second, according to Niu Er's law, support force can be calculated indirectly

I hope I can help you. If you have any questions, you can ask ~ ~ ~
I wish you progress in your study and make progress

8. Judge what? Force point or force object

9. The supporting force of one object is the reaction of the object to the pressure of another. That is to say, pressure and support are a team of balance forces, as well as a pair of forces and reactions.