When its tangential speed is constant
<span>Although the speed of an object that has a uniform circular motion is constant, its velocity is </span>not constant<span>. Not only that, but it is actually changing constantly.</span><span>
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The energy carried by a photon is equal to
(Planck's Konstant) times (the frequency of the photon) .
Planck's konstant is 6.626 x 10⁻³⁴ m²-kg/s (rounded)
This column actually appears due to the body parts reflecting the light of the sun or moon to the observer.
If the body is not perfectly smooth, only parts of this body would be at the correct position to reflect the light of the sun or moon to the observer.
If the body was perfectly smooth, it would act like a mirror where you can see the full image of the sun or the moon reflected on it.
Before a person walks through burning coal, the person will make sure their feet are very wet. When they start walking on the coal, this moisture will evaporate and form a protective gas layer underneath the person's feet. You can see examples of this if you happen to drip some water on a hot stove or any very hot surface. The water will very easily glide around on top of a newly formed layer of air underneath it -- like air hockey pucks on an air hockey table. Note that when someone walks through burning coal, typically this is also done very quickly to prevent a great deal of exposure to possible harm. By walking quickly, thinking positively, and letting the water cushion you from immediate danger over a short distance, such a task is possible. You may have also heard of physics teachers demonstrating how this principle works by sticking their hand first in a bucket of water and then quickly in a bucket of boiling molten lead. In the lead, their hand is protected briefly by a layer of gas from the evaporated water (the water vapor). I'm fairly sure that there is a name for this particular layer of gas, but I'm afraid the name is beyond me at the moment. In other words, water vapor has a low heat capacity and poor thermal conduction. Very often, the coals or wood embers that are used in fire walking also have a low heat capacity. Sweat produced on the bottom of people's feet also helps form a protective water vapor. All of this together makes it possible, if moving quickly enough, to walk across hot coals without getting burned. WARNING: Do not attempt to perform any of the actions described above. You can seriously injure yourself. Answered by: Ted Pavlic, Electrical Engineering Undergrad Student, Ohio St. (citing my source)
Answer:
The potential energy of an object is the energy possessed by the object due to its position in a gravitational field.
Mathematically, it is given by:
where
m is the mass of the object
g is the acceleration due to gravity at the location of the object
h is the height of the object
As we can see, the potential energy depends on the height of the object, h.
However, this height is relative, since it can be measured using different reference levels.
Generally, the reference level is taken to be the ground; so for example, an object located at the top of a cliff 40 m above the ground, has
h = 40 m
But this value is of course relative, since we can also take the reference level to be the top of the cliff, so in that case, we would have
h = 0
