# How can we evaluate properly the work (energy) performed by the muscles?

## How do you calculate work done by a body?

The amount of work done is directly proportional to the magnitude of force applied, as well as the displacement of the object.

How to Calculate Work Done by a Force.

Work done by FX : WFX = F ∙ d ∙ cosθWFX = 20 ∙ 10 ∙ cos30°WFX = 173.21 J
Work done by Ff : WFf = Ff ∙ d ∙ cosω

## What is work and how does it apply to energy?

Work is the transfer of mechanical energy from one object to another. Since work is a movement of energy, it is measured in the same units as energy: joules (J).

## What is the formula of work-energy?

Overview of Work, Energy and Power

What is Work, Energy and Power?
Work
Formula The energy stored in an object due to its position and height is known as potential energy and is given by the formula: P.E. = mgh
Unit The SI unit of energy is Joules (J).
Power

## What happens to the energy of the one doing the work and to the object on which work is done?

Answer: When work is done on a system or object, energy is added to it. When work is done by a system or object, it gives some of its energy to something else. … By applying a force on the ball over this distance, the hand is doing work on the ball, and the ball gains kinetic energy.

## What is work and work done?

W = (|F| cosθ) |d| We know that work done is defined as the multiplication of magnitude of displacement d and the component of the force that is in the direction of displacement.

## What is work done by a body?

Work done on a body is equal to the increase in the energy of the body, for work transfers energy to the body. If, however, the applied force is opposite to the motion of the object, the work is considered to be negative, implying that energy is taken from the object.

## When work is done on a body its energy?

Body gains energy when work is done on a body. This energy is stored in the form of either potential or kinetic energy.

## How can doing work cause a change in energy on a body?

Energy is the ability of a person or an object to do work or to cause a change. When you do work on an object, some of your energy is transferred to the object. You can think of work as the transfer of energy. In fact, both work and energy are measured in the same unit, the joule.

## What is an example of work energy?

Lifting a weight from the ground and putting it on a shelf is a good example of work. The force is equal to the weight of the object, and the distance is equal to the height of the shelf (W= Fxd). Work-Energy Principle –The change in the kinetic energy of an object is equal to the net work done on the object.

## How do you solve work done problems in physics?

Apply the work equation to determine the amount of work done by the applied force in each of the three situations described below.

1. Diagram A Answer: W = (100 N) * (5 m)* cos(0 degrees) = 500 J. …
2. Diagram B Answer: W = (100 N) * (5 m) * cos(30 degrees) = 433 J. …
3. Diagram C Answer: W = (147 N) * (5 m) * cos(0 degrees) = 735 J.

## How will you relate work power and energy with each other?

Force exerted on an object over a distance does work. Work can increase energy, and energy can do work. Power is the rate at which work is done.

## Can you measure work done and kinetic energy in calories Why?

Answer: Yes. Explanation ⇒ The Kinetic Energy is the energy possessed by the body by virtue of its motion. Now, we know that the physical quantity does not depends upon the unit used, but it matters that every unit used in the mathematical expression should belongs to the same system of the units.

## How do you measure the work done on an object and how does work relate to the power delivered to an object?

The quantity which has to do with the rate at which a certain amount of work is done is known as the power. The metric unit of power is the WATT. As is implied by the equation for power, a unit of power is equivalent to a unit of work divided by a unit of time. Thus, a watt is equivalent to a joule/second.

## Can kinetic energy be measured in calories?

When you measure the temperature of something, you’re measuring the average kinetic energy of the individual particles. … The calorie is a fairly small amount of heat — the amount it takes to raise the temperature of 1 gram of water 1°C. The kilocalorie (kcal), which is 1,000 calories, is a convenient unit of heat.

## Is a calorie a measure of work?

The calorie was originally defined as the amount of heat required at a pressure of 1 standard atmosphere to raise the temperature of 1 gram of water 1° Celsius. Since 1925 this calorie has been defined in terms of the joule, the definition since 1948 being that one calorie is equal to approximately 4.2 joules.

## What is the measurement of energy?

Joules measure energy. We have a whole guide to help you better understand what a joule is, but we’ll quickly break it down here. Electricity’s main unit of measurement is power, which is the rate of energy consumption. If a watt (power) is one joule per second, then a joule of electrical energy is one watt-second.

## What is the body’s main source of energy?

carbohydrates

Grains — along with fruits, vegetables, and dairy — contain carbohydrates, the body’s main source of energy.

## How is calories determined?

Calories are calculated from the added energy values of fat, protein, and carbohydrates. FDA Nearly all packaged foods we eat have a nutritional label. The amount of calories on that label is a guiding factor in helping consumers make good or bad food choices.

## How is the energy value of foods determined?

The energy value is determined based on the mass of the food and water and the increase in temperature.

## How do they measure protein in food?

Because proteins are made up of chains of amino acids joined by peptide bonds, they can be hydrolysed to their component amino acids, which can then be measured by ion-exchange, gas-liquid or high-performance liquid chromatography. The sum of the amino acids then represents the protein content (by weight) of the food.

## Which equipment is used to experimentally determine how much energy is in food?

A calorimeter is a piece of equipment designed to measure the energy released or absorbed during a chemical reaction or phase change. Food calorimetry allows us to determine the number of calories per gram of food.

## How is energy measured in an experiment?

Calorimetry

1. pour cold water into a boiling tube.
2. record the starting temperature of the water.
3. record the mass of the food sample.
4. heat the food until it catches fire.
5. heat the water using the flame from the burning food.
6. record the final temperature of the water.

## How does the Atwater system work?

The Atwater system uses the average values of 4 Kcal/g for protein, 4 Kcal/g for carbohydrate, 9 Kcal/g for fat and 7 Kcal/g for alcohol that were determined by burning these substances in a calorimeter.

## How can we compare energy in food in a school lab?

Quote from the video:
Energy equals mass times specific heat capacity times change in temperature crucially the mass is the mass of water heated.

## How is the energy content of food related to the work it can do?

Energy content is an important property of food. The energy your body needs for running, talking, and thinking comes from the food you eat. … Dividing the resulting energy value by grams of food burned gives the energy content (in J/g).

## How do you test the energy content of food?

You can determine energy content of food by burning a portion of it and capturing the heat released to a known amount of water. This technique is called calorimetry. The energy content of the food is the amount of heat produced by the combustion of 1 gram of the food, and is measured in kilojoules per gram (kJ/g).