How to calculate body fat percentage

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In summary, the conversation is discussing how to calculate a man's percent body fat based on his weight in water and the densities of fat, muscle, and water. It is mentioned that it is acceptable to use the weight in pounds as mass in grams, and it is explained that this is because the units will cancel out in the equation. The total mass is then calculated as the sum of the mass of muscle and fat. The conversation then shifts to discussing the relationship between weight and volume, and the concept of Archimedes Principle is mentioned as a way to determine the man's volume.
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Homework Statement


A 180 lb man weighs 5 lb in water. What is his percent body fat? Assume that fat has a density of 0.90 g/cc and muscle has a density of 1.06 g/cc. Water has a density of 1.0 g/cc.

Although we are given the weight in lbs, it is okay to work with it like mass (as grams) or even as buoyant force...why?

Is this bc both sides of the equation (mass of fat and mass of muscle) will be in the same unit, so it doesn't matter?

What is the total mass? m-total = m-muscle + m-fat

This was the first question of a series of questions and I don't understand how we can calculate the mass without a volume...I don't understand the relationship between the weight and volume displaced.
 
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Yes, all forces in the question arise as mass * gravitational acceleration, so the gravitational acceleration cancels out.
Can you state Archimedes Principle, and see what it tells you about the man's volume?
 

1. How do I calculate my body fat percentage?

To calculate your body fat percentage, you will need to measure your weight and body circumference at specific points, such as your waist, hips, and neck. Then, use a formula that takes into account your gender, age, and these measurements to determine your body fat percentage.

2. What is the formula for calculating body fat percentage?

The most commonly used formula for calculating body fat percentage is the U.S. Navy Body Fat formula. This formula uses your weight, waist, hip, and neck measurements, along with your gender and age, to estimate your body fat percentage. There are also various online calculators available that use different formulas to calculate body fat percentage.

3. Is there an accurate way to calculate body fat percentage?

While there are formulas and calculators available to estimate body fat percentage, the most accurate way to calculate it is through a body fat measurement test performed by a professional. These tests use specialized equipment, such as DEXA scans or Bod Pod measurements, to determine your body fat percentage with a high level of accuracy.

4. How often should I calculate my body fat percentage?

The frequency of calculating your body fat percentage depends on your goals and personal preference. If you are trying to lose weight or track progress, it may be beneficial to calculate your body fat percentage every 4-6 weeks. However, it is not necessary to do so more frequently unless advised by a healthcare professional.

5. What is a healthy body fat percentage?

The recommended body fat percentage varies based on gender and age. Generally, a healthy body fat percentage for men is between 10-20%, and for women, it is between 18-28%. However, it is important to note that body fat percentage is just one aspect of overall health, and it is essential to focus on overall wellness rather than a specific number.

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