After talking about the boats and webpage for weeks...
and
... here's our conclusion:
A simple floating boat seems like a very common situation, but there are a lot of different physics components to this scenario. We neglected many possible complications to keep the scenarios simple, but it still gets complex. We answered a lot of questions with our research, but there is always more to learn, both in physics and in web design!
Some more thoughts about the boats
(aka Reflection Questions)
Here are some thoughts and reflection regarding how the boats float and move across the water.
I.After developing explanations using forces and energy, what do you understand better? (What can you explain now that you could not before this assignment?)
This project has made us understand a number of topics better. We now know how to explain why some things float while others do not using density. This also explains buoyant forces, which we had questions about when we started the project. Our energy diagrams helped us see why so much fuel is needed for boats because not all of the energy from the fuel becomes kinetic. This also helped us understand why boats are not that environmentally friendly, because product from the reaction of the fuel gets let out into the air. We also got to explore where energy from the wind comes from, instead of just saying it appears. The rowboat situation we examined also helped us understand why it takes so much effort to row a boat. The energy cubes showed us that a lot of energy is lost, so more energy has to be put in. The energy for these three scenarios helped us compare the different ways boats can be used as transportation, and look at the efficiencies of each.
Rowboat (aka Dragon Boat)
The conditions for this scenario are also idealized. There are no waves creating extra motion and the boat is moving at constant velocity, so there is no acceleration.
Free Body Diagram
The gravitational and buoyant forces directly oppose each other in magnitude and direction because the boat is not accelerating in either of those directions. There is a Fpush in this scenario that is applied by the rowers, causing the boat to move in that direction. There is also the Fdrag applied to the boat. Since air resistance is still negligible compared to the water resistance, air resistance was left out of the diagram. The Fdrag and the Fpush are opposite because the Fdrag opposes the direction of motion. They are also equal in magnitude because the boat is not accelerating. Since the boat is not accelerating, the net force is zero. The diagram demonstrates this because all of the force vectors cancel out.
Energy Cubes
Sailboat
In a situation where a boat is using a sail to move across the water, the boat is being pushed by the wind. Our diagram represents a time when the boat is moving at constant speed with zero acceleration and there are no waves moving across the water.
Free Body Diagram
As described in other scenarios, the gravitational force and the buoyant force acting on the boat cancel out because there is no acceleration in that direction. The push force causing the boat to move comes from the wind that is pushing in the direction of motion. In the situation shown above, the sail is perpendicular to the direction of motion and only the force from the wind in the direction of motion is considered. When the sail or the wind is at a different angle, the force vectors have different components. For simplicity, only the ideal situation with the push force from the wind perpendicular to the motion is depicted. The last force on the diagram is the Fdrag. As discussed earlier, the amount of drag from the air is negligible compared to the drag from the water, so air resistance is left out of this diagram. The Fdrag is opposite the Fpush and they are equal in magnitude because the boat is not accelerating. The net force in this diagram is zero, showing that the boat is moving at a constant velocity.
Energy Cubes
Propeller (aka Cruise Ship) Boat
In this situation, a propeller is used to move the boat in one direction. The boat is moving at a constant velocity, so there is no acceleration. We are also using an ideal situation where the boat is moving across a still lake with no waves.
Free Body Diagram
There is a buoyant force acting the in direction opposite the gravitational force. These two forces are equal and opposite because the boat is not accelerating in either of those directions. There is the Fthrust that is applied by the propeller, moving the boat in that direction. The drag force in this case is mostly applied by the water as it resists the movement of the boat. There is a negligible amount of drag from the air, so it has been left out of the diagram. The Fdrag is opposing the Fthrust, so they are acting in opposite directions. They are also equal in magnitude because the boat is not accelerating. The net force is zero, indicating that the boat is moving at a constant velocity.
Energy Cubes
The first scenario we will look at is a boat sitting on a still lake with no net movement.
Peaceful Floating Boat
Free Body Diagram
This first diagram shows the forces acting on a boat when it is sitting on a perfectly smooth body of water. In this ideal situation, the only forces acting on the boat are gravity and the buoyant force of the water. These forces perfectly balance each other, so the net force in this situation is zero. This shows that the boat is at rest with no movement.
Energy Cubes
How do boats float?
The buoyant force is a little mysterious in how it works. Looking at some of the ginormous boats that carry hundreds of passengers, logically that boat should not stay above the water. However, a simple understanding of density answers all of these mysteries.
Density is the amount of mass per volume. When you look at an anchor, a lot of mass takes up a small volume. The anchor is very dense, even more than the water. Because the anchor has more mass in an amount of volume than water, it will sink. When a large cruise ship is considered, it would make sense that because it has so much mass, it would sink. This doesn’t happen, though, because cruise ships are filled with a lot of air. All of this air lowers the density as the mass of the ship then takes up more space. If the same amount of volume is considered with water and with the ship, the ship actually has less mass. This means that it is less dense, and will therefore float.
This difference in density is described as the buoyant force that pushes up on the boat and keeps it from sinking. This force also directly opposes the gravitational force in both direction and magnitude. The reasoning for buoyant force in this situation also holds for all of the other scenarios discussed later.
Other Scenarios - Floating Boat ( please click me!)
What can forces and a boat create when they work together? Think about it...!
Drum roll...
Yes, Titanic a boat moving across the water!!
Have you been on a boat?
Have you ever wondered how you stayed above the water,
席薇雅很久沒來部落格了...這幾年來，席薇雅一直掛心著部落格，可是卻一直不知道為什麼的找盡所有的藉口，就是不願意找時間好好的坐下來更新。
轉眼間，時間過了好幾年，席薇雅也從費城搬到西雅圖了。說到西雅圖，很多人想到的，不外乎電影「西雅圖夜未眠」，Starbucks，微軟，還有最近鬧得沸沸揚揚的波音。其實，美國有很多公司都把他們的總部設在西雅圖（包括周邊地區），Amazon.com的總部也在這裡唷！（呵呵，席薇雅這幾年對Amazon.com真是愛不釋手，雖然有時候服務不是最好的，但是已經非常方便了！省去很多時間在採購日常用品上！）
席薇雅現在正在西雅圖（事實上，應該算是美國西北部）最大，最負盛名的學殿：University of Washington華盛頓大學唸書！UW（U Dub）的社工系是全美Top 3的呢！席薇雅相當幸運的能進到如此優秀的學院進修，真的充滿了感激之情！！不過呢，進了研究所之後，席薇雅也發現，研究所真的不簡單！每週都有幾百頁的閱讀，還有報告要寫，每天能睡個6小時就已經是小確幸。不過席薇雅相信，這一切的奮鬥都會在將來成為甜美的果實！（OS: 話雖如此，奮鬥的過程還是好辛苦啊～～～！）
席薇雅現在的目標：希望可以在未來持續更新部落格 :)
天～～搬家還真不是一般的累...
尤其是... 當東西一堆如山又沒車的時候... 天啊～～
席薇雅從來都不知道自己有那麼多東東... 一直到了期末大掃除時才發現...
兩大行李箱外加三小紙箱再加一個巨無霸紙箱的東西...
席薇雅花了將近30小時才真正的整理完... 30小時馬拉松式的整理, 幾乎一直站著,連喘息的機會都沒有...
