# Tag Info

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From Wikipedia: Paraffin wax is a white or colorless soft solid derivable from petroleum, coal or oil shale, that consists of a mixture of hydrocarbon molecules containing between twenty and forty carbon atoms. As stated above, paraffin wax is a hydrocarbon that is a soft solid at room temperature. When it melts, it becomes the combustible fuel for the ...

0

Thinking out of the box i have brought an answer to this that works on paper. By using the forces listed in the original question (Balloon lift @ 6lbs and payload @ 8oz) i have included the following forces as being necessary to engineer a solution. First the weight+gravity for the pulley (I list at 4oz), secondary pulley system (.5oz friction force i will ...

3

Let $m_1$ be the mass of the peas, which we'll assume to be mainly water, $m_2$ the mass of boiling water added and $m_p$ the mass of the pan. We'll assume no heat losses. After adding everything to the pan and allowing for thermal equilibrium to be established the temperature of pan, water and peas is $T$. $T$ can be calculated from the adiabatic heat ...

1

It is more difficult because it requires more energy. Once you are up to speed, walking on a flat surface requires only enough energy to overcome friction, air resistance, and the energy to move your legs. Walking up stairs is more difficult because you additionally have to provide the energy to lift your body weight up the stairs. It's the difference ...

1

When moving up you are pushing yourself in the opposite direction of the force of gravity. Therefore you do a positive work which is approximately $mgh$ ($h$ is the height of the step). While coming down gravity will do the same work for you.

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You have to lift up your body mass under the presence of gravity, so you have to overcome the force of gravity. While climbing up the stairs you have to put force on ground, more then your weight, which put same force but in opposite direction i.e. on you. Suppose your mass is $m$, then while climbing up, if you resolve the forces then, N-mg=ma\text{, } ...

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If you take the exact moment the wheels hit the ground, before the board moves forward, there is no difference between dropping straight down and coming in at say 45 degrees. This is no big deal dropping from a metre, but from a greater height, your body may not be able to absorb the impact without damage, before you transfer your potential energy into ...

0

This is not trivial, but is routinely done in laboratories and commercial products (like surround stereo systems). If we consider the strictly physical aspects of sound localization in humans (and probably many other living beings who cannot conscientiously orientate their ears), there are two main phenomena to take into account: 1. Interaural time ...

1

Basically the whole kinetic energy is transfered to pressure, and then this pressure will be transfered to kinetic energy again; this time only the direction is as defined by hydrostatic pressure; perpendicular to surface. This above gives a following basis; Kinetic energy of the ball is also it's potential energy (no friction on fall) Ekin = m g H This ...

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Just to add to what Floris has said. It is frequent (in the UK) that institutional settings would have toughened glass in windows, particularly in bathrooms, gyms etc. that would have the form of a wire mesh (of order 1cm grid) embedded in the glass. That would do a particularly good job of blocking phone signals that would otherwise penetrate the glass.

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In general the answer is "yes it is possible" - but in your case the answer is "that is not a Faraday cage". Radio waves are (partially) reflected by any discontinuity in dielectric constant of the medium they propagate through. The ones that propagate (through walls etc) will also experience attenuation. A faraday cage is a continuous conducting structure ...

4

A crude model of the UTE is used simulate the pressure field created by the car as it travels through atmospheric air. We must determine the pressure in truck bed because it applies force on the surfboard. The car travels at a constant $60 ~\text{mph}$ (an arbitrary, worst-case value). UPPER: The velocity profile of air flowing around the car. ...

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The ground effect that is used in the F1 cars make a large pressure differential between the upper and the lower board surfaces. If the air can flow freely bellow the surfboard it will fly away, otherwise it is 'glued' to your truck. Be precautious and lock it mechanically. EDIT ADD. The board behaves like a wing flying near the ground. Above it's upper ...

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Sorry but surf boards do fly out. You may not have experienced it personally but keep doing it the way you are and you are bound to experience it. If you are thinking that as the velocity of the air travels over car it is some how holding the boards in you are incorrect. Check out this article http://www.gcdataconcepts.com/carairflow.html "Actually the ...

0

DC is more dangerous in one respect in that it causes more electrolysis in the tissues than AC.

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This question can be answered with a nice visual comparison. Let's take a pan of water, and put it on the stove at full power. You periodically throw in an ice cube to keep it at room temperature. Obviously, the moment you stop doing this, your pan is going to heat up very quickly. Now, take that same pan and put it in a slightly colder place. Intuitively, ...

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