---
title: "A beaker partially filled with water rests on a digital scale that measures the normal force exerted on the beaker. A solid metal block suspended by a vertical string is slowly lowered into the water until it is fully submerged. The block is held stationary and does not touch the bottom or sides of the beaker, and no water spills out. The reading on the digital scale increases. Which of the following statements provides the correct physical explanation for why the scale reading increases?"
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url: "https://nerd-notes.com/ubq/122691/"
date_modified: "2026-09-28T11:02:41+00:00"
---

# A beaker partially filled with water rests on a digital scale that measures the normal force exerted on the beaker. A solid metal block suspended by a vertical string is slowly lowered into the water until it is fully submerged. The block is held stationary and does not touch the bottom or sides of the beaker, and no water spills out. The reading on the digital scale increases. Which of the following statements provides the correct physical explanation for why the scale reading increases?

A beaker partially filled with water rests on a digital scale that measures the normal force exerted on the beaker. A solid metal block suspended by a vertical string is slowly lowered into the water until it is fully submerged. The block is held stationary and does not touch the bottom or sides of the beaker, and no water spills out. The reading on the digital scale increases. Which of the following statements provides the correct physical explanation for why the scale reading increases?

![A schematic drawing of a laboratory setup. A horizontal digital scale rests on a flat surface. On top of the scale sits an open cylindrical beaker containing water. A solid rectangular block is fully submerged in the water, hanging from a single vertical string that extends upward out of the frame. The block is suspended in the center of the liquid without touching the sides or bottom of the beaker. No arrows, force vectors, or mathematical notations are present.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1790593360-NiE9td.jpg)

- **A.** The reduction in upward string tension causes the unsupported fraction of the block's gravitational force to be transmitted through the fluid column directly onto the base of the beaker.
- **B.** The displaced water increases the height of the water column in the beaker, which increases the total mass and gravitational force of the fluid resting above the scale.
- **C.** The water exerts an upward buoyant force on the submerged block, so by Newton's third law the block exerts an equal-magnitude downward force on the water, increasing the normal force exerted by the scale on the beaker.
- **D.** The upward buoyant force acting on the block and the additional downward force detected by the scale constitute a Newton's third law action-reaction pair between the block and the scale.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/122691/*