Understanding Surface Gravity and Acceleration in the Moon and Earth

In summary, NASA's Moon/Earth Comparison Data sheet lists the surface gravity at 9.80 m/s2 and the surface acceleration at 9.78 m/s2. Surface gravity refers to the acceleration due to gravity at the surface of a body, while surface acceleration takes into account the effect of the earth's rotation, resulting in a slightly lower value. This is due to the fact that some of the gravitational force is needed for centripetal acceleration to keep objects in a circular path with the Earth's surface. The surface acceleration varies depending on location, with the lowest value being near the equator. This information can be found on NASA's fact sheets for the moon and Earth.
  • #1
Mitchell
7
0
In a Moon/Earth Comparison Data sheet I received from NASA, they list the surface gravity at 9.80 m/s2. They also list surface acceleration at 9.78 m/s2. What is surface acceleration? All the problems relating to gravity in my Physics text (so far) calls Earth's gravity constant as 9.80 m/s2.
 
Physics news on Phys.org
  • #2
Surface gravity is the acceleration due to gravity at the surface of a body (this is used for physics problems that happen close to the ground). I would think surface acceleration is the same thing, but I'm not sure why NASA lists it as 9.78.
 
  • #3
Maybe they are factoring in the rotation of the earth.
 
  • #4
THis is due to the effect mentioned in that other thread! (k12 zone) THe "surface gravity" is the actual gravitational field strength "g" at the surface of the earth. The unit of this field strength should properly be N/kg, but this unit is equivalent to m/s^2.

The actual "free-fall" acceleration will be less than "g" because due to the rotation of the earth, some of the gravitaitonal force is required for centripetal acceleration (to keep us going in a circle with the Earth's surface). This surface accelration changes depending on where you are in the world. It is least near the equator, where "g" will be reduced by 0.033 m/s^2.
 
  • #6
That should satisfy Mitchell. :smile:
 
  • #7
It sure does and thank you to everyone.
 

What is Surface Gravity?

Surface gravity refers to the gravitational force experienced by an object on the surface of a planet or other celestial body.

How is Surface Gravity calculated?

Surface gravity is calculated using the equation F = GmM/r^2, where F is the force of gravity, G is the gravitational constant, m is the mass of the planet, M is the mass of the object, and r is the distance between the center of the planet and the object.

What factors affect Surface Gravity?

The factors that affect surface gravity include the mass and size of the planet, as well as the distance between the object and the planet's center. The shape and rotation of the planet can also have an impact on surface gravity.

What is the difference between Surface Gravity and Standard Gravity?

Surface gravity refers to the force of gravity experienced on the surface of a celestial body, while standard gravity is a value used to measure the strength of gravity at Earth's surface. Standard gravity is equivalent to 9.8 meters per second squared (m/s^2).

Why is Surface Gravity important?

Surface gravity is important because it determines the weight of objects on a particular planet or celestial body. It also plays a crucial role in the formation and evolution of planets and other objects in the universe.

Similar threads

Replies
5
Views
293
  • Other Physics Topics
Replies
14
Views
21K
Replies
54
Views
2K
  • Astronomy and Astrophysics
Replies
10
Views
2K
  • Special and General Relativity
Replies
10
Views
1K
  • Other Physics Topics
Replies
32
Views
5K
  • Astronomy and Astrophysics
Replies
33
Views
3K
  • Astronomy and Astrophysics
Replies
15
Views
1K
Replies
22
Views
658
  • Special and General Relativity
2
Replies
62
Views
3K
Back
Top