What is force of gravity to do with 9.81?

Answer 1

The force due to gravity is called your weight. This force causes an acceleration.

The acceleration due to gravity on the earth is 9.81 m/s/s.

W = m g

g = acceleration due to gravity = 9.81 m/s/s

Answer 2

Newton theorized that the acceleration of gravity in the vicinity of any mass is g times (that mass)

divided by the (distance between that mass and the place where the acceleration due to its gravity

is measured) squared . Therefore, with the mass of the Earth, and the distance from the Earth's

center when you're on the surface, the acceleration of gravity at the Earth's surface is 9.81 meters

per second-squared.

Answer 3

You are referring to the gravitational acceleration, not force, at the surface of the earth. The negative shows that the acceleration is downward. The 0.81 value is due to the entire mass and the radius of the earth. A more massive planet will create a large gravitational acceleration. A larger radius will creat a smaller gravitational acceleration.

Newton' 2nd law of motion states that force is proportional to the product of acceleration and mass. So to calculate force you must multiple this gravitational acceleration by some mass that it is acting upon.

A 6 kg Bowling ball will have a gravitational force of 6 x 9.81 = 58.86 newtons

(force is measured in newtons). A car of perhaps 1500 kg will have a gravitational force of 1500 x 9.81 = 14,715 newtons.

Answer 4

It's not really the 'gravitational constant' ... that's something else.

The 'acceleration due to gravity' on the Earth is 9.8 meters per second2

as the result of the Earth's mass and radius.

Answer 5

The numeric value depends on the system of units used. 9.8 meters/second2 is the value if you use the SI system. If you prefer feet to meters, it is about 32 feet/second2.

The amount of gravity depends on the gravitational constant, the masses involved, and the distance. In the case of Earth, the effect of gravity is the same as if all the mass were concentrated at the center of Earth. In other words, you can plug the mass of planet Earth into the formula, and for the distance, use Earth's radius (since normally you would be doing calculations for things that happen near Earth's surface).

Answer 6

Force is the derivative of the Gravity Energy, E = -mGM/r.

For example , F = d/dr -mGM/r= mG/r2 = mg.