I'm a visual learner and I have to either be shown or be able to imagine it in my minds eye (like with wave phenomenon.). I just can't get to an understanding of electricity with my resources.
Does anybody know of basic Physics videos explaining concepts at a rudimentary level? Like on YouTube or something?
I've kinda hit a brick wall in my studying. I need help on electric fields and electric potential and electric potential energy.
I'm pretty solid on particles, newtons three laws, wave phenomenon, and the quantum stuff. I just can't wrap my head around the electric stuff. Any help would be appreciated.
Lol, I'm still not understanding it from your guys's explanations, the book, or Wikipedia.
To put it bluntly, I remember our teacher telling us that one was a "fictitious force". You're following a trajectory, but this makes it feel outward. I'm pretty sure this was centrifugal. Like the spaceship ride at the carnival.
Centripetal is the inward push?
I'm at the point where I might skip this question if asked. (We can skip four.). If he even asks this.
But I'd rather skip the quantum mechanics stuff than something this "easy."
Put simply: They are the opposing forces involved in radial motion.
The Centripetal force is the force that pushes towards the center of the arc. It is responsible for the arc being maintained.
The Centrifugal force is the force that pushes away from the center of the arc. It is the counter force that tries to make the object to move in a straight line.
Taking the common example of a bucket of water being spun on a rope:
When the bucket is spun around, the force that keeps the bucket in the radial motion is the Centripetal force pushing (or pulling, if you'd prefer) it back in (in this example it is applied by the rope).
Countering that is the centrifugal force, it pulls the bucket away from the center, as seen in the tension in the string. This is indirectly illustrated by water being forced away from the center of the arc. That occurrence is not directly because of the centrifugal force on the bucket, but is is related.
If you consider the water on it's own, it too is traveling radially.
The Centrifugal force of that motion is evident, it is what forces the water against the bottom of the bucket.
Considering that, the Centripetal then also becomes obvious. It is the bucket pushing back on the water, stopping it from breaking through the bottom.
It is important to note that while the centrifugal force is applied to objects, it is not applied by any particular object, but is a result of the frame of reference used. This is why it is sometimes stated that it doesn't exist, because it is a fictitious force needed to correct the frame of reference.
I don't think explaining exactly where it comes from would be covered by your course, so I'm not going there because it's a little hard for me to describe succinctly.
On the first question, though, I hate to use speed to characterize things in relativity because sometimes I feel the terms are ambiguous. I like to think in terms of events (waves encountered) and time. "come at you faster" just feels ambiguous.
Frequency you hear is determined by the number waves that reach your ear per second.
I would say that as I approach a wave source, the number of waves that hit my ear per second increases, and as I move away, the number of waves that hit my ear per second decreases.
though maybe others would find that more confusing.
No that does sound better. My professor marks off for confusing things, so more explanation is always better.
Number two is wrong. Jostling an electron can create an EM wave, but it's not involved in propagating the EM wave. From Wikipedia, an EM wave is "a self-propagating transverse oscillating wave of electric and magnetic fields". Basically, a moving charge will create a magnetic field, and that magnetic field will keep the charge moving, which will create a magnetic field, which will keep the charge moving... and on and on and on.
Why is there a Doppler effect when the source of a sound is stationary and the listener is in motion? In which direction should the listener move to hear a higher frequency? A lower frequency?
There is a Doppler effect because the person is either moving towards the object when make the waves come at you faster. Or moving away from an object when make the waves come slower. To obtain a higher frequency you'd move toward the object. To obtain a lower frequency you'd move away from the object.
What produces an electromagnetic wave? What maintains an electromagnetic wave?
The jostling of an electron creates an electromagnetic wave. The electron bumps into other electrons to maintain the wave.
Why can't we see stars in the daytime?
Because the atmosphere scatters the light from the sun into a bright blue. This light is strong enough that it makes dimmer lights (such as stars) impossible to see.
Edit: I don't feel confident I got these three answers "correct".
"turn an incandescent bulb on and off quickly while holding your hand a few inches from the bulb. You feel it's heat, but when you touch the bulb it isn't hot. Explain this in terms of radiant energy and the bulb's transparency."
I feel like that question is misleading - a bulb would be hot to the touch if it has been on for some period of time.
If that's not true, however, I think you stumbled across the answer. In addition, yeah, if that's the case, then a "murky" colored bulb should be warmer.
Okay --
This is what I put:
The light bulb is clear so it gives off most of it's radiant energy through radiation and thus sends waves of heat toward your hand. Radiation is the transfer of energy by means of electromagnetic waves. When you touch the transparent bulb, there is very little conduction because the bulb itself is not hot. If I left the bulb on long enough it would become slightly hotter than room temperature, but it is sending off it’s radiant energy through waves and the filament is not heating up the actual bulb. If a lightbulb was murky or colored in some way less radiant energy would be able to escape and the bulb would be hotter than a transparent bulb.
This was my conclusion:
There’s a difference between heat transfer (holding our hands away from the bulb) and temperature (touching the bulb). Heat transfer is the energy that flows from a substance of higher temperature to a substance of lower temperature through conduction, convection, and radiation. Temperature is the measure of average speed of molecules per area per size given other considerations. The heat is being transferred via radiant energy because the bulb is translucent; it is not storing any of this energy in the bulb and that’s why it is room temperature to the touch.
Also, what you have is a mixture, not a compound. Small vocabulary nitpick. Oil is a compound, water is a compound, and oil+water is a mixture of two compounds.
Your explanation about soap acting as a bridge is correct. The best way to think of soap molecules is shaped like a balloon on a string. The string is a long chain of carbons and is hydrophobic. The balloon is ionic and is charged, which makes it hydrophilic. The molecules of soap "pierce" tiny droplets of oil with their tails and coat the oil droplet with charged, hydrophilic balloons. It essentially gives the tiny oil droplets water-loving jackets.
Yes, 30 seconds. I'll change the vocabulary between mixture/compound.
Thanks Viricide and dcartist!
Sorry for the double post.*
Okay, I can't find the answer to this on the internet. Looking pretty hard.
Why does a lightbulb feel warm when you hold your hand up to it but is room temperature when you touch it?
Is it because the light bulb is clear so it gives off all it's radiant energy through radiation and thus sends waves of heat toward your hand? If a lightbulb was murky or colored in some way would it be hot to the touch?
I've been to Wikipedia.
I'll try those sites though.
I'm a visual learner and I have to either be shown or be able to imagine it in my minds eye (like with wave phenomenon.). I just can't get to an understanding of electricity with my resources.
I've kinda hit a brick wall in my studying. I need help on electric fields and electric potential and electric potential energy.
I'm pretty solid on particles, newtons three laws, wave phenomenon, and the quantum stuff. I just can't wrap my head around the electric stuff. Any help would be appreciated.
24. What is a quantum matter wave? What is waving in a quantum matter wave?
25. How does treating the electron as a wave rather than as a particle solve the riddle of why electron orbits are stable and discrete?
last two questions I'll need help with Physicson ever! Lol.
To put it bluntly, I remember our teacher telling us that one was a "fictitious force". You're following a trajectory, but this makes it feel outward. I'm pretty sure this was centrifugal. Like the spaceship ride at the carnival.
Centripetal is the inward push?
I'm at the point where I might skip this question if asked. (We can skip four.). If he even asks this.
But I'd rather skip the quantum mechanics stuff than something this "easy."
Centrifugal force pushes outward and keeps the water in the bucket?
Okay, so do they form a Newton's third law pair?
Why does the number of protons and neutrons determine whether if an atom is stable or radioactive?
No that does sound better. My professor marks off for confusing things, so more explanation is always better.
Thanks Stardust.
Why is there a Doppler effect when the source of a sound is stationary and the listener is in motion? In which direction should the listener move to hear a higher frequency? A lower frequency?
There is a Doppler effect because the person is either moving towards the object when make the waves come at you faster. Or moving away from an object when make the waves come slower. To obtain a higher frequency you'd move toward the object. To obtain a lower frequency you'd move away from the object.
What produces an electromagnetic wave? What maintains an electromagnetic wave?
The jostling of an electron creates an electromagnetic wave. The electron bumps into other electrons to maintain the wave.
Why can't we see stars in the daytime?
Because the atmosphere scatters the light from the sun into a bright blue. This light is strong enough that it makes dimmer lights (such as stars) impossible to see.
Edit: I don't feel confident I got these three answers "correct".
"turn an incandescent bulb on and off quickly while holding your hand a few inches from the bulb. You feel it's heat, but when you touch the bulb it isn't hot. Explain this in terms of radiant energy and the bulb's transparency."
I thought one of the laws of thermodynamics was heat always transfers hot to cold.
Edit:
Dcartist, the project / miniature lab says to turn on a light bulb that's been off for a while. Then turn it on for a couple minutes then touch it.
The project does not say to touch a bulb that's been on for a while.
[I can post the full question if you desire.]
Okay --
This is what I put:
The light bulb is clear so it gives off most of it's radiant energy through radiation and thus sends waves of heat toward your hand. Radiation is the transfer of energy by means of electromagnetic waves. When you touch the transparent bulb, there is very little conduction because the bulb itself is not hot. If I left the bulb on long enough it would become slightly hotter than room temperature, but it is sending off it’s radiant energy through waves and the filament is not heating up the actual bulb. If a lightbulb was murky or colored in some way less radiant energy would be able to escape and the bulb would be hotter than a transparent bulb.
This was my conclusion:
There’s a difference between heat transfer (holding our hands away from the bulb) and temperature (touching the bulb). Heat transfer is the energy that flows from a substance of higher temperature to a substance of lower temperature through conduction, convection, and radiation. Temperature is the measure of average speed of molecules per area per size given other considerations. The heat is being transferred via radiant energy because the bulb is translucent; it is not storing any of this energy in the bulb and that’s why it is room temperature to the touch.
Yes, 30 seconds. I'll change the vocabulary between mixture/compound.
Thanks Viricide and dcartist!
Sorry for the double post.*
Okay, I can't find the answer to this on the internet. Looking pretty hard.
Why does a lightbulb feel warm when you hold your hand up to it but is room temperature when you touch it?
Is it because the light bulb is clear so it gives off all it's radiant energy through radiation and thus sends waves of heat toward your hand? If a lightbulb was murky or colored in some way would it be hot to the touch?
* - No worries; fixed.