Physics - Classical Mechanics - Weight: The Force of Gravity

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Hey it's a me again @drifter1! In this article we will continue with Physics, and more specifically the branch of "Classical Mechanics". Today's article will be about Weight: The Force of Gravity. So, without further ado, let's get straight into it!

Weight Force w

We already used the weight w of an object in various topics and problems of Physics.

The weight w is equal to the product of an object's mass m and the gravitational acceleration g caused by the force of gravity that attracts the object to the Earth for example.

Thus, mathematically the force of gravity can be described by the following equation:

For Earth we use the accelaration of gravity on the surface of the Earth at sea level, which is: g = 9.8 m/s2.

Gravitational Acceleration g

The gravitational acceleration that an object acts on another object, can be calculated by substituting F with m ⋅ g in Newton's Law of Gravity:

The mass m gets cancelled on both sides giving us an equation for calculating g.

Thinking about planets we can describe the distance d as the radius of a planet r plus the relative height of the object h to the surface of the planet, giving us:

Gravity on Earth

Let's calculate the value of Earth's gravity at the Earth's surface and some Km's above the surface. Earth's mass is approx. 5.98 × 1024 Kg and the typical radius is 6.38 × 106 m.

Inserting this information in the previous equation we get:

For twice the distance (d = 2 ⋅ r) we get:

Gravity on Other Planets of the Solar System

From Ref2 remade in quicklatex.






Mathematical equations used in this article, where made using quicklatex.

Previous articles of the series

Rectlinear motion

Plane motion

Newton's laws and Applications

Work and Energy

Momentum and Impulse

Angular Motion

Equilibrium and Elasticity


Final words | Next up

And this is actually it for today's post!

Next time we will talk about Gravitational Fields....

See ya!

Keep on drifting!
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