how does mass differ from weight
what is law of universal gravitation
Mass is the amount of a substance present. It is the same on earth, on the moon, or anywhere else. Weight is the attraction of an object by gravity. The mass of a man is the same whether on earth or on the moon but the weight of a man on the moon is about 1/5 that of the weight on earth because the attraction due to gravity is less on the moon.
To understand the difference between mass and weight, let's start with their definitions:
1. Mass: Mass is a measure of the amount of matter in an object. It is an intrinsic property and remains the same regardless of the object's location in the universe. The SI unit of mass is the kilogram (kg).
2. Weight: Weight, on the other hand, is the force with which an object is pulled towards the center of the Earth (or any other celestial body). It depends on the mass of the object and the gravitational pull acting on it. The SI unit of weight is the Newton (N).
To find the weight of an object, you need to multiply its mass by the acceleration due to gravity. The value of the acceleration due to gravity varies depending on location, but on the Earth's surface, it is approximately 9.8 meters per second squared (9.8 m/s^2). The formula to calculate weight is:
Weight = mass × acceleration due to gravity
Now, let's move on to the law of universal gravitation:
The law of universal gravitation was formulated by Sir Isaac Newton and describes the force of gravitational attraction between two objects. According to this law:
Every particle of matter in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
Mathematically, the law of universal gravitation can be expressed as:
F = (G × m1 × m2) / r^2
Where:
- F is the gravitational force between two objects,
- G is the gravitational constant (approximately 6.674 × 10^-11 N m^2/kg^2),
- m1 and m2 are the masses of the two objects, and
- r is the distance between the centers of the two objects.
This law explains how objects attract each other due to gravity, regardless of their masses, as long as they have mass and are separated by a distance. It helps us understand the motion of planets, moons, satellites, and other celestial objects.