3.2.1 Model: Buoyancy
A buoyant force (FB) is the upward force, exerted on a body, by a fluid (Cengel & Cimbala, 2013: 98). The calculation of the buoyancy would be vital as the total weight of the mechanism cannot exceed the buoyancy force. This would result in the mechanism sinking.
Figure 3.1 illustrates a free body diagram of the buoy with the forces acting on it. The buoy is spherical and has a diameter of 110 mm.
Figure 3.1: Free-body diagram of buoy
Because the buoy will be placed in the ocean, the density of water (ρw) can be assumed to be 1000 kg/m3. Due to the density of the HDPE being less than that of water, namely 970 kg/m3, the heave-plate would also experience a buoyancy force.
F_B=W= ρ_s.g.V
FB = Buoyancy
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When the buoy is heaved up by the wave, the heave plate would resist the upward movement of the buoy, resisting the pull. The buoy would then be pulled down under its own weight when the buoy falls in the crest part of the wave.
The heave-plate was to be made of HDPE as it is a non-corrosive material in saltwater and relatively light when compared to other materials such as galvanised steel, stainless steel or aluminium.
The depth of the heave-plate was important to calculate as the lower the heave-plate was placed, the greater volume of water acting on the plate. If the heave-plate was placed too close to the surface of the ocean, the plate would oscillate up and down with the buoy. The heave-plate would then not serve its purpose. The pressure force exerted on the heave plate had to be greater than the force exerted by the wave on the buoy (the upward pull). This would allow the buoy to be heaved by the wave, while the heave-plate would remain unmoved.
The calculation below was done to determine the minimum depth the heave-plate has to be in order to serve its purpose as a damping
Sink or Float Introduction: I am doing this experiment to find the density of aluminum foil to see if it floats or sinks when placed in water. I hope to find out how the density of aluminum foil changes when weight is added to the foil. I hypothesize that the boat will hold 20 pennies before sinking. You will need to get: Aluminum foil Pennies Water And a big container or tub for your boat to float in. Procedure: 1.
of tides. High - water heights vary from 22 to 28 feet and low - water heights
- The plumb bob was used to locate the centre of the trip plate , to
Rachel begins by stating that when tides or waves occur in the ocean they don’t just effect the surface but also the deepest levels of the water. How would you know for a fact that the wave currents run deeper than just the surface? Proof given by her illustrates
2. http://www.chs.k12.nf.ca/socstud/ssgrassroot/OceanRangerLesson.htm. 3. http://en.wikipedia.org/wiki/drill_string. 4.
Biomechanics is the overall topic that will be discussed throughout the presentation, this incorporates a brief discussion about water resistance, propulsion and buoyancy. Under lifesaving, appropriate techniques and the choice of stroke for the Timed Tow will be analyzed and justified.
This was allowing large waves to build. Unfortunately, the ship was no longer protected by land.
Incorporating both the Lagrangian and Eulerian measurements allowed researchers to measure both surface and sub surface currents. The floating devices, which scientist call a ‘drifter’, to take the measure surface current as well as devices which scientist call a ‘profiling floats’ ,...
In the experiment these materials were used in the following ways. A piece of Veneer wood was used as the surface to pull the object over. Placed on top of this was a rectangular wood block weighing 0.148-kg (1.45 N/ 9.80 m/s/s). A string was attached to the wood block and then a loop was made at the end of the string so a Newton scale could be attached to determine the force. The block was placed on the Veneer and drug for about 0.6 m at a constant speed to determine the force needed to pull the block at a constant speed. The force was read off of the Newton scale, this was difficult because the scale was in motion pulling the object. To increase the mass weights were placed on the top of the ...
To do a front dive a diver pushes his hips upward just slightly as he leaves the board. After he had begun to go up into the air, he throws his arms downward just enough to make is upper torso rotate around his hips. At the peak of the dive, the diver tightens his stomach muscles and pulls his legs up towards the sky, leaving his body in a perfect upside-down position to enter the water head-first.
The boat floats on the water according to Archimedes Principle which states an immersed object is buoyed up by a force equal to the weight of the fluid it displaces. The force applied downwards by earth’s gravity coupled with the upward force of buoyancy allows the boat to float. The boat consists of separate components each having their own center of mass, or center of gravity. The boat, the occupant(s), the engine or oars, and the fishing gear all combine to create a whole unit. The center of mass for the whole system is the average of the center of mass of each component. These components may move relative to each other but as a whole cannot change its velocity or momentum without the application of an external force. Newton’s first law of motion states that an object at rest stays at rest unless a force is exerted upon it. For the boat to move through the water a force must be exerted upon it. The forces that move the boat can be the current of the water, the rowing of the oars, the engines propeller, and wind. As the boat moves through the water a Doppler Effect is created. The Doppler Effect applies to all
“Ten Things You Should Know About Marine Debris.” NOAA.gov. (n.p), (n.d.). Web. 10, Apr., 2014.
The next theory is the Methane Gas Theory, “a large amount of methane gas is known to exist below the ocean floor trapped in the sediments in form of methane hydrates. If such gas finds its way out and starts rising through the water, it can significantly reduce the density of water in that area. And ships passing over that area can sink in no time. Such gas release can also create explosions and
against the water and to move the hull higher. The force of the water against
Henderson, T. n.d. The physics classroom tutorial. Lesson 2: Force and Its Representation [Online]. Illinois. Available at: http://gbhsweb.glenbrook225.org/gbs/science/phys/class/newtlaws/u2l2b.html [Accessed: 28th March 2014].