Acceleration due to gravity

Definition

Acceleration due to gravity is the rate at which an object accelerates towards the Earth or any other celestial body due to the force of gravity. This acceleration is approximately $$9.81 \, m/s^2$$ on the surface of the Earth and varies slightly depending on location and altitude, reflecting the influence of factors such as the Earth's rotation and its shape.

5 Must Know Facts For Your Next Test

1. The standard value for acceleration due to gravity is $$9.81 \, m/s^2$$, but it can be affected by altitude and geological variations.
2. Near Earth's surface, all objects experience the same acceleration due to gravity, regardless of their mass, which was famously illustrated by Galileo's experiments.
3. Acceleration due to gravity decreases as you move further from the Earth's center, following an inverse square relationship based on distance.
4. The variation in acceleration due to gravity can cause differences in weight measurements for objects at different elevations, such as mountains versus sea level.
5. On other celestial bodies, like the Moon or Mars, acceleration due to gravity is significantly lower than on Earth, impacting how objects move and behave.

Review Questions

• How does acceleration due to gravity relate to free fall and what implications does this have for objects in motion?
  • Acceleration due to gravity directly impacts free fall, as it determines the rate at which objects accelerate towards Earth when they are dropped. In a vacuum where air resistance is negligible, all objects fall at the same rate of approximately $$9.81 \, m/s^2$$ regardless of their mass. This means that in ideal conditions, both a feather and a hammer would hit the ground simultaneously if dropped from the same height, demonstrating that gravity affects all masses equally.
• Discuss how changes in elevation can affect measurements of acceleration due to gravity and its practical applications.
  • As elevation increases, acceleration due to gravity decreases because you are moving farther away from the Earth's center. This change can be practically observed in geophysical studies where precise measurements are needed for activities such as surveying and mineral exploration. For example, an accurate understanding of how gravity varies with altitude helps engineers design buildings and structures that account for these differences.
• Evaluate how Newton's law of universal gravitation connects to acceleration due to gravity and impacts our understanding of gravitational interactions in space.
  • Newton's law of universal gravitation establishes that all masses attract each other with a force that depends on their masses and the distance between them. This law explains why objects experience acceleration due to gravity: it's the result of Earth's mass exerting a gravitational pull on objects near it. Understanding this connection allows us to predict how celestial bodies interact, such as how satellites orbit Earth or how planets maintain their paths around the Sun, illustrating the fundamental principles governing motion in space.

Related terms

gravitational force:

The attractive force that pulls two masses toward each other, proportional to their masses and inversely proportional to the square of the distance between their centers.

free fall: The motion of an object solely under the influence of gravity, without any air resistance or other forces acting on it.

Newton's law of universal gravitation: A fundamental principle stating that every point mass attracts every other point mass in the universe with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.