#ionaphysics

[mlarrier]

Light

I've just given this some thought, the question of "Does light accelerate?"  Now at first glance, the answer would be no, because the speed of light is the the highest velocity at which anything can travel (so far as we know).  Therefore, it would be argued that for light to accelerate, it would have to travel faster than the speed of light.  This, is not always true, however.  If I remember correctly (feel free to add to this @IonaPrepPhysics), light loses speed when bent in a prism. So things like drops of water (rain and snow included), fiber optics cables, and other types of prisms would slow down the light. When it exits those prisms, however, the light should start speeding up, correct?  Or has the energy already been lost? And what happens in terms of a laser?

[taylorgangorphysics-blog]

Mechanical Advantage is a very well demonstrated by this cartoon, which depicts the relationship between exerted force, the resistance force, and the distance moved; all of which are components of the formulas we have learned over the last few classes for Actual and Ideal Mechanical Advantage: AMA= Force(out)/ Force(in); IMA = Distance(in)/ Distance (out).

[taylorgangorphysics-blog]

Golf & Physics

While discussing graphite golf shafts with my father this morning I came to a realization about the work that goes into these devices. It became apparent to me that a shaft's "flex" value (which, just as it sounds, is the tendency to bend during a swing) is trying to maximize Actual Mechanical Advantage. The flex value's main function is to allow players with various swing speeds (anywhere from 50 mph to 125 mph) to achieve the maximum level of torque as the club head approaches the ball. This is done by adjusting the flex of an amateur's shaft (usually under 90 mph) to a "regular" or "senior" flex, which bends more; and by giving mid-amateur's (competitive) and professionals (usually tops out at 128, which is Tiger's club head speed) "stiff" or "extra stiff" flexes so that the torque might also be maximized. It gets progressively more complicated as you begin to look into tip, mid, and top flexes which control trajectory (throwback), but I'll leave the advanced stuff for our next Golf & Physics lesson.

[taylorgangorphysics-blog]

While this is not a picture of the kind of mechanic efficiency in the sense that we discussed today in class, it is a bit of comic relief. The actual measure of mechanical efficiency comes from dividing the actual mechanical advantage by the ideal one, which are calculated by dividing the "out force" by the "in" one, and the "in distance" by the "out" one, respectively. 

[taylorgangorphysics-blog]

This picture is a representation of the way pulleys reduce the amount of force exerted in a system. Each time a wheel is crossed over, due to increased distance, the force must be reduced; and this image depicts the mathematical relationship between the values of the weight each time a different pulley is added.

[taylorgangorphysics-blog]

Gallows

Today in class we learned about the viability of pulleys in their reduction of work output. And while I had significant difficulties in preparing my set of gallows for experimentation, I was eventually able to once again conclude that the world makes sense. This overtly broad inference was drawn from my realization that utilizing more pulleys leads to an increase in distance which leads to less required force. It's almost as if this stuff is magic.

[taylorgangorphysics-blog]

Today in class we learned about Potential Energy, as opposed to Kinetic; there was a bit of confusion about the classifications of various expenditures of energy in the world around us. I thought that this diagram would help clarify a bit, especially if one understands why each form of energy is in the category that it is. For instance, all of the energy in the objects on the left are stationary (a tennis racket's energy is in the tension of the strings); whereas the energy in the objects on the right are transitive (wind's energy is a moving force which is very apparent to anyone who has had the misfortune of trying to hit a wedge shot uphill into a 25 mph gust).

[taylorgangorphysics-blog]

I know this is a bit of a throwback to uniform circular motion, but this posed a question to me (not involving James Bond): does UCM involve work? I became curious when I thought that there was force, and distance in a rotating system; however, I also began to think that perhaps there was a difference because the distance could be canceled out because the object in question returned to its original position.