Question

Собака легко перетаскивает утопающего в воде, однако на берегу она не может сдвинуть его с места. Почему?

Answer 1

На человека действует сила архимеда.

Answer 2

Why can a dog easily drag a drowning person in the water but not move them on land?

When it comes to a dog's ability to drag a drowning person in the water but not move them on land, there are a few factors at play.

1. Buoyancy: In water, objects experience buoyancy, which is an upward force exerted by the water that helps support their weight. This buoyant force makes it easier for a dog to pull a person in the water because the person's weight is partially offset by the buoyancy.

2. Friction: On land, the person's weight is not offset by buoyancy, making it more difficult for a dog to move them. Additionally, the friction between the person's body and the ground creates resistance, making it harder for the dog to overcome the static friction and initiate movement.

3. Leverage: Another factor is the difference in leverage. In water, the dog can use the buoyancy and the water's resistance to its advantage, allowing it to use its body position and strength more effectively to pull the person. On land, the dog may not have the same leverage due to the lack of buoyancy and the increased friction.

4. Surface area: The surface area in contact with the ground also plays a role. In water, the person's body is surrounded by water, which reduces the surface area in contact with the dog. This reduced surface area makes it easier for the dog to exert force and drag the person. On land, the person's entire body is in contact with the ground, resulting in a larger surface area and more resistance to movement.

In summary, a dog can easily drag a drowning person in the water due to buoyancy, reduced friction, leverage, and reduced surface area. On land, the lack of buoyancy, increased friction, lack of leverage, and larger surface area make it more difficult for the dog to move the person.

I hope this explanation helps! Let me know if you have any further questions.