In modern physics, mass is defined as the amount of matter an object contains. It is a fundamental property of matter and is measured in units of kilograms (kg). Mass is one of the key factors in determining an object's behavior and interactions in the physical world.
In modern physics, mass and weight are often used interchangeably, but they are actually two distinct concepts. Mass is a measure of the amount of matter in an object, while weight is a measure of the force of gravity acting on an object. Mass remains constant regardless of location, while weight can vary depending on the strength of gravity at a particular location.
In modern physics, mass and energy are closely related through Einstein's famous equation, E=mc^2. This means that an object's mass can be converted into energy and vice versa. The more massive an object is, the more energy it contains, and the more energy is required to change its state or motion.
In modern physics, mass is often measured using a device called a mass balance or scale. This device compares the weight of an object to a known standard mass, allowing scientists to determine the mass of the object being measured. Other methods, such as particle accelerators, are also used to determine the mass of subatomic particles.
In modern physics, mass is considered to be a conserved quantity, meaning it cannot be created or destroyed. This is a fundamental principle in physics known as the law of conservation of mass. However, mass can be converted into other forms of energy and vice versa, as seen in nuclear reactions and particle collisions.