PHLB09H3 Lecture : Lecture notes

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maroonarmadillo957

1 Jun 2011

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1: it"s prohibited to interrupt the course of nature by killing yourself, then. 2: your free will is a part of nature! Re: against nature you can"t save yourself either going against nature . 1: it"s only against your community if you owe your community . 2: could even be a benefit (eg. captain oates) The claim is that god put me here, so only god can take me away. If you reply that your parents decision was guided by god . Then i can respond by saying my life and decisions are also guided by. It can"t be consistent with your autonomy to undermine the principle. But you can"t commit suicide, which by definition is with self-intent, Sheds doubt on kant"s claim that suicide is inconsistent with a person"s interests: more reasons to be suspicious of kant"s claim . If i am going into a permanent coma .

Related Questions

A stent is a small, tubular device implanted into arteries orsome other hollow organ in order to provide structural supportagainst collapse. Some modern stents can even provide gradual drugdelivery. Clinical failures are some of the most serious reasonsfor continual R&D into stent improvement. Models are anindispensable part of further research as experimental testing isoften expensive and time-consuming. For example, a stent with a10-year life expectancy corresponds to approximately 400 millioncyclic loadings from heartbeats!

A common design for a stent is a hollow woven mesh of helicalwire, as shown in the above figure. Much like Chinese finger traps,a change in length is accompanied by a corresponding change inradius of the stent. The goal of this problem is to examine howthis deformations are coupled.

(a) Letâs start out by looking at a single helix of wire.Convince yourself that we can parametrize the curve of the wireby:

x(Î¸) =rcosÎ¸

y(Î¸) = rsinÎ¸

z(Î¸) = (lÎ¸/2Ï)sinÎ±

where r is the radius and Î± is the âlead angleâ of the helix -the angle the wire makes with the xy-plane as it crosses it, and lis the length of wire in one turn of the helix. Determine thislength of wire l in one turn of the helix by using l =â« ds withappropriate bounds, where ds =â(dx²+dy²+dz² ). Express l in terms of rand Î±.

I would appreciate help with any of the following problems. Thankyou.

22. In an isometric exercise a person places a hand on a scale andpushes vertically downward, keeping the forearm horizontal. This ispossible because the triceps muscle applies an upward forceperpendicular to the arm, as the figure indicates. The forearmweighs 22.1 N and has a center of gravity as indicated. The scaleregisters 113 N. Determine the magnitude of .
Distance between the force applied by the muscle and the elbowjoint 0.025 m. The distance between the elbow joint and the armscenter of gravity is 0.15 m. Distance between the arms center ofgravity and the center of the scale is 0.15 m. I was not able tofind the answer to this problem using the solution posted on thewebsite.

26.A wrecking ball (weight = 4310 N) is supported by a boom, whichmay be assumed to be uniform and has a weight of 2550 N. As thedrawing shows, a support cable runs from the top of the boom to thetractor. The angle between the support cable and the horizontal is32Â°, and the angle between the boom and the horizontal is 48Â°. Find(a) the tension in the support cable and (b) the magnitude of theforce exerted on the lower end of the boom by the hinge at pointP.

56. Two identical wheels are moving on horizontal surfaces. Thecenter of mass of each has the same linear speed. However, onewheel is rolling, while the other is sliding on a frictionlesssurface without rolling. Each wheel then encounters an inclineplane. One continues to roll up the incline, while the othercontinues to slide up. Eventually they come to a momentary halt,because the gravitational force slows them down. Each wheel is adisk of mass 3.64 kg. On the horizontal surfaces the center of massof each wheel moves with a linear speed of 5.26 m/s. (a),(b) Whatis the total kinetic energy of each wheel? (c), (d) Determine themaximum height reached by each wheel as it moves up the incline. Iwas able to solve for the rolling wheel but couldn't find the rightanswers for the sliding wheel.

66. A thin uniform rod is rotating at an angular velocity of 1.89rad/s about an axis that is perpendicular to the rod at its center.As the figure indicates, the rod is hinged at two places,one-quarter of the length from each end. Without the aid ofexternal torques, the rod suddenly assumes a "u" shape, with thearms of the "u" parallel to the rotation axis. What is the angularvelocity of the rotating "u"?

76. A woman who weighs 501 N is leaning against a smooth verticalwall, as the drawing shows. Find (a) the magnitude of the force N(directed perpendicular to the wall) exerted on her shoulders bythe wall and the (b) horizontal and (c) vertical components of theforce exerted on her shoes by the ground.

3. 3 Stratosphere-troposphere exchange

The rate of exchange of air between the troposphere and thestratosphere is critical for determining the potential of variouspollutants emitted from the surface to reach the stratosphere andaffect the stratospheric ozone layer. One of the first estimates ofthis rate was made in the 1960s using measurements of strontium-90(90Sr) in the stratosphere. Strontium-90 is a radioactive isotope(half-life 28 years) produced in nuclear explosions. It has nonatural sources. Large amounts of 90Sr were injected into thestratosphere in the 1950s by above-ground nuclear tests. Thesetests were banned by international treaty in 1962. Following thetest ban the stratospheric concentrations of 90Sr began to decreaseas 90Sr was transferred to the troposphere. In the troposphere,90Sr is removed by wet deposition with a lifetime of 10 days (bycontrast there is no rain, and hence no wet deposition, in thestratosphere). An intensive stratospheric measurement network wasoperated in the 1960s to monitor the decay of 90Sr in thestratosphere. We interpret these observations here using a 2-boxmodel for stratosphere-troposphere exchange with transfer rateconstants kTS and kST (yr-1) between the tropospheric andstratospheric reservoirs. The reservoirs are assumed to beindividually well-mixed.

Let mS and mT represent the masses of 90Sr in the stratosphere andin the troposphere respectively. Observations of the decrease inthe stratospheric inventory for the period 1963-1967 can be fittedto an exponential mS(t) = mS(0)exp(-kt) where k = 0.77 yr-1.

1. Write mass balance equations for mS and mT in the 1963-1967period.

2. Assuming that transfer of 90Sr from the troposphere to thestratosphere is negligible (we will verify this assumption later),show that the residence time of air in the stratosphere is tS =1/kST = 1.3 years.

3. Let m'T and m'S represent the total masses of air in thetroposphere and the stratosphere, respectively. Show that theresidence time of air in the troposphere is tT = tS (m'T/m'S) = 7.4years. Conclude as to the validity of your assumption in question2.

4. Hydrochlorofluorocarbons (HCFCs) have been adopted asreplacement products for the chlorofluorocarbons (CFCs), which werebanned by the Montreal protocol because of their harmful effect onthe ozone layer. In contrast to the CFCs, the HCFCs can be oxidizedin the troposphere, and the oxidation products washed out byprecipitation, so that most of the HCFCs do not penetrate into thestratosphere to destroy ozone. Two common HCFCs have trade namesHCFC-123 and HCFC-124; their lifetimes against oxidation in thetroposphere are 1.4 years and 5.9 years, respectively. There are noother sinks for these species in the troposphere. Using our 2-boxmodel, determine what fractions of the emitted HCFC-123 andHCFC-124 penetrate the stratosphere.

PHLB09H3 Lecture : Lecture notes

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