When a piece of wood is suspended from the hook of a spring balance, it reads 70 gf. The wood is now lowered into water. What reading do you expect on the scale of spring balance?

Explanation

To solve the problem step by step, we will analyze the situation of the piece of wood being suspended in air and then submerged in water.

### Step-by-Step Solution:

1. **Identify the weight of the wood in air**:
The spring balance reads 70 gf when the wood is suspended in air. This means the weight of the wood in air is 70 gf.

2. **Understand the concept of buoyancy**:
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