Here's why:
* Newton's Law of Universal Gravitation: This law states that every particle in the universe attracts every other particle with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between their centers.
* Earth's Gravitational Acceleration: The force of gravity acting on an object near the Earth's surface is commonly referred to as its weight. This force is determined by Earth's gravitational acceleration (g), which is approximately 9.8 m/s².
* Calculating Force: The force (F) is calculated by multiplying the mass (m) of the object by the gravitational acceleration (g): F = m * g
Therefore, for a 1 kg body:
* F = 1 kg * 9.8 m/s²
* F = 9.8 Newtons
Important Note: The actual gravitational force can vary slightly depending on factors like altitude and location on Earth.
