How much will a body of `70 N ` weight in water if it displaces 20 ml of water ?

Answer

To solve the problem of how much a body weighing 70 N will weigh in water if it displaces 20 ml of water, we can follow these steps:

### Step 1: Understand the weight of the body
The weight of the body in air is given as 70 N.

### Step 2: Convert the volume of water displaced to mass
We know that the density of water is approximately 1 g/ml. Therefore, if the body displaces 20 ml of water, we can find the mass of the water displaced:
- Mass of water displaced = Volume of water displaced × Density of water
- Mass of water displaced = 20 ml × 1 g/ml = 20 g = 0.02 kg

### Step 3: Calculate the weight of the water displaced
To find the weight of the water displaced, we can use the formula:
- Weight = Mass × Gravitational acceleration (g)
- Here, g is approximately 9.8 m/s².
- Weight of water displaced = 0.02 kg × 9.8 m/s² = 0.196 N

### Step 4: Calculate the apparent weight of the body in water
The apparent weight of the body in water can be calculated using the formula:
- Apparent weight = Weight in air - Weight of water displaced
- Apparent weight = 70 N - 0.196 N = 69.804 N

### Final Answer
The weight of the body in water, after accounting for the buoyant force, is approximately **69.804 N**.

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