Question

решите пжл)))три бруска. Первый покоится, второй движется по инерции без трения, третий движется под действием силы F. В каком случае совершается механическая работа? А. Только в 1. Б. Только во 2. В.Только в 3. Г. Во 2 и З.

Answer 1

ответ Г,т.к мехническое движение -изменение  положения тела в пространстве относительно других тел с течением времени и тела взаимодействуют по законам механики.

Answer 2

The Scenario

We have three blocks: the first one is at rest, the second one is moving with inertia and no friction, and the third one is moving under the influence of a force F. We need to determine in which case mechanical work is being done.

Analysis

To determine if mechanical work is being done, we need to consider the definition of work. In physics, work is defined as the product of the force applied to an object and the displacement of the object in the direction of the force. Mathematically, work (W) is given by the equation:

W = F * d * cos(theta)

Where: - W is the work done - F is the force applied - d is the displacement of the object - theta is the angle between the force and the displacement vectors

Let's analyze each case:

Case 1: First block at rest

In this case, the first block is at rest. Since there is no displacement, the work done is zero. Therefore, mechanical work is not being done in this case.

Case 2: Second block moving with inertia and no friction

In this case, the second block is moving with inertia and no friction. Although there is a displacement, there is no external force acting on the block. Therefore, the work done is zero. Mechanical work is not being done in this case.

Case 3: Third block moving under the influence of force F

In this case, the third block is moving under the influence of a force F. There is both a displacement and an external force acting on the block. Therefore, mechanical work is being done in this case.

Conclusion

Based on the analysis above, mechanical work is only being done in Case 3: Only in the third scenario where the third block is moving under the influence of force F.

Please let me know if you need any further clarification!