Physics

The correct statement is: The net external force acting on the block is zero.

To analyze the situation where a block is sliding down a vertical wall at a constant speed under the action of a horizontal pushing force FFF, we can examine the forces acting on the block.

Given Information:

The block is sliding down at constant speed.

This implies that the net force acting on the block is zero (Newton's first law).

Analyzing the Statements:

Option A: The net external force acting on the block is zero.

Correct. Since the block is moving at a constant speed, the forces acting on it must be balanced. Thus, the net external force is zero.

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