Unit Three - Summary

Unit Blog Summary- Unit three

What did I learn this unit?

            Unit three shed light on forces, revealing the rules of their interactions. We started with Newton’s third law every action has an equal and opposite reaction. That led to the understanding of action reaction pairs. An apple sitting on a table has the action reaction pair, “table pushes apple up/ apple pulls table down”. With that basic foundation we were able to build different rooms creating a home for forces. The first wall was the problem of the horse and buggy, it also addressed the age old question of how to win tug of war. The answer was quite simple apply more friction than the other team. Since all forces are equal and opposite you can only pull as hard on the other team as they pull on you, so whichever team has more friction with the ground will win, accelerating the other team towards them. Next was gravity, and how it affected tides. Gravity can be calculated by [ force of gravity = (mass1)(mass2) / (distance)(distance) ]. Once the wall was up, we made a window to understand the moon, and tides. We found out that there are two high and low tides each day, each high and low are twelve hours away.  Tides are caused by the difference in gravitational forces on opposite sides of the earth.

 

The above image shows the different types of tides, exemplifying how the movement of the moon decides the height of tides. It is important to mention the Spring tides happen once every 28 days, the length it takes for the moon to orbit the earth. The next wall we built was made of momentum. Momentum is represented by P, and the formulas for momentum and relating topics are bellow. Momentum cannot be destroyed, it can only be transferred. We proved this in our lab, as we raced the carts into each other. This lead to the question of how do you stop without hurting yourself? The answer was to spread out your impulse, which is equal to change in momentum. Impulse is equal to force (time). Since they multiply together to reach their total they are directly proportional. When there is more time less force is required to perform the same change in momentum, which will mean less damage to the object.  In all we built an elaborate home for forces, building in small nuances in the base boards and closets, creating a new horizon of understanding.

What are some things students may have forgotten while working on this unit?

·         That gravity is proportional to distance and mass

·         That every action has an equal and opposite reaction

·         That impulse is not a force

·         Tides are caused by the difference in forces felt on each side of the earth

·         That you can only push as hard as the other person or object can push back

Formulas from the unit

•  Change in Momentum= Impulse
•             Momentum = mass ( velocity)
•             Impulse = force (time)
• Change in momentum = final momentum – Initial momentum

How is this Relevant to the real world?

            This unit shows why things break, how tides work, why we have tides, and how we walk, how to win in tug of war, and much more. Forces govern the world we live in. This has been the most practical unit ye, showing practical uses daily.