Newton’s Third Law of Motion, The Law of Action and Reaction states…”For every action there is an equal and opposite reaction.
I work in the construction industry and Newton’s Third Law of Motion, The Law of Action and Reaction is an important aspect of construction building process. The Third Law helps us determine how much weight or load a structure can hold; and without the Third Law, we would not have the towering structures and bridges we have in place today.
I will address how Newton’s Law applies on the bearing loads of a structure, the weight transfer of loads throughout the structure, the consequences of a mistake in calculating the load a structure can hold and how the weight above ground has to be supported by the soil below.
When we think of towering skyscrapers, we don’t think about all the components required to build that structure. We look up in awe at the buildings height and beauty and never give a thought to structural design investigation, structural mechanics and all the hard work that goes into building a magnificent structure.
Physics has an important role in the construction industry because without concerns for the actions of forces on physical bodies of the materials, structural failure could result. From design to completion, physics formulas and calculations are required to ensure that a structure will not fail and Newton’s Third Law of Action and Reaction is applied in this process.
For every action, there is an equal and opposite reaction. There are many components that must be addressed prior to breaking ground to build a towering structure. Before even thinking about putting a shovel to the ground, we must first select a building site that can bear the load of the structure; as not all soil can sustain towering structures and bridges such as clay and sand and silty soils.
The bearing load of the building is the most important detail of this construction because the weight loads that are transferred throughout a building are tremendous. The bearing point is the spot or location where the weight of the structure is placed in a continuous flow. The bearing point will flow like a straight line from the top of the structure to the very bottom. The Architect/Engineers will calculate the weight to the footing that is then transferred to the soil to support the bearing point of the structure by incorporating Newton’s Third Law.
The example here shows how the force of one thousand lb/ft is transferred in a flow from the top of the example structure to the footings then down to the soil where we can clearly see Newton’s Third Law, “that for every action there is an equal and opposite reaction” taking place. In the example, the forces generated from the soil is flowing in an upward motion meeting the downward flow of the building material which when met puts the building structure in equilibrium.
Active Force (Load) 1000 lb/ft
Reactive Forces R1 R2
500 lb ...