Tagged Questions

Concerns the application of the laws of physics to analyze common situations encountered in everyday life.

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3
votes
3answers
737 views

Why it is difficult to drink tea with a straw?

It is easy to drink cold drinks, soft drinks with straw but when I tried to drink tea with straw then that was very unpleasant and even for time I lost the sense from my tongue. My question is why it ...
0
votes
4answers
286 views

Does car lose kinetic energy when turning?

I am writing simple car simulation. Assume non friction, then in straight line the car doesn't lose speed. But what if the car is turning, there should be some kinetic energy loses to change the ...
2
votes
1answer
271 views

Why does a cooling motorcycle make popping noises?

I was sitting in my parked car tonight when a Harley-Davidson motorcycle parked next to me. With my window down, I could hear that as the motorcycle was cooling down, it was giving off some type of ...
0
votes
4answers
277 views

Can we create invisible things?

We are able to see this beautiful world because of light. When light gets reflected from the object, the reflected light enters our eye retina and thus we are able see that particular object from ...
0
votes
3answers
66 views

Would it be possible to distinguish rap and singing from just seeing the soundwaves?

For any person even remotely familiar with music it is obvious that rap and singing are easily distinguishable (save for some interesting mix styles). This means that there must be a clear difference, ...
3
votes
2answers
272 views

How do I figure out the momentum of a water balloon when it reaches the person I am throwing it at?

Recently an experiment was performed in which myself and a partner filled a water balloon and threw it back and forth at each other without breaking it. We gradually increased the distance at which it ...
91
votes
6answers
8k views

Very strange shadow phenomenon

I was laying on my bed, reading a book when the sun shone through the windows on my left. I happened to look at the wall on my right and noticed this very strange effect. The shadow of my elbow, when ...
10
votes
4answers
3k views

Why does my door shut faster when the window is open?

I've noticed that if I shut my door when the window is open in a room, the door will tend to shut faster. If I shut the door when the window is closed with a normal force it will not fully close as if ...
37
votes
4answers
7k views

How do bicycle spokes work?

As you know, it is quite obvious that Bicycle spokes attach the hub in the centre to the rim. What else do they do? If you compare the wheels today with the ones from ancient times, there are more ...
0
votes
1answer
122 views

why do we Carbonate drinks not any other gas

Carbonation is done in all fizzy drinks. Also it forms a small amount of carbonic acid which we feel on our tongue. We can diffuse oxygen as well in the water at higher level. Except for acid ...
0
votes
0answers
49 views

What creates black streams in fountain-type fireworks?

For the New Year celebration of 2014, my nephews set off a series of fountain-type fireworks (as shown below). When one looks carefully into the shower of light, one notices that a fair number of ...
2
votes
1answer
46 views

Predicting the direction of sound incorrectly? [closed]

When i was sitting outside my house yesterday, I heard a strange sharp sound. I could not point out it's exact direction but apparently looked like coming from left but later my friend told me that an ...
3
votes
2answers
199 views

How does the pressurization in a house's water supply allow adjustable flowrates from a tap?

John Rennie's answer to this question got me thinking about the water supply in a house. I know that water supplies are normally operated at an over-pressure with respect to atmospheric pressure to ...
4
votes
4answers
317 views

Why do the passing objects' shadows run in the direction of the moving train?

While travelling in the train on the sunset, I have noticed the strange phenomenon. The shadows of the lonely trees and lampposts, that stay along the railroad, are moving on the wall in the same ...
1
vote
2answers
181 views

Why are turns banked?

I have seen everywhere that where on road, on railway track when there is a turn then one side of that road or railway track is below the surface or some what down then actual surface. Any one ...
-2
votes
1answer
77 views

What is the physics concept in sponge filter

I really need help I want to ask what is the physics concept in Sponge Filter?
1
vote
3answers
322 views

Why do I still get static shocks when hands are wet?

Quite a few times now I have washed my hands, and while my hands are still wet I will touch something metal and get a static shock. I thought static electricity doesn't really build up when there's a ...
6
votes
2answers
173 views

Is it possible to estimate the speed of wind by the sound emitted by a cable of an overhead power line?

I was near ($\approx40m$) an overhead power line and I heard a sound coming from the cables of the power line; I think the sound was made by the vibrations of the power cables due to the wind but I am ...
4
votes
3answers
71 views

Why don't fogbows appear on clouds?

As far as I know clouds are lot of small droplets condensed in air. If droplets are large enough we see a rainbow. If they are small we see a fogbow. Although the size of the droplets are big enough ...
2
votes
3answers
171 views

Why does centre of mass of ice-container system shift in absence of any net external force?

Consider a cube of ice in a flat based container(the base is very broad).The temperature of the system is at first fixed at a minus Celsius temperature, but then the system is left on a table with the ...
2
votes
2answers
109 views

Why would the reflection of a lamp by a bowl look like a heart?

I have this bowl roughly the shape of a circular truncated cone, and the lamp shines on the bowl at an angle. The reflected lamp light hit the bottom of the bowl and created a light ring that looks ...
6
votes
3answers
700 views

Gravitation law paradox for very close objects?

We all know that gravitation force between two small (not heavenly) bodies is negligible. We give a reason that their mass is VERY small. But according to inverse square law, as $r\to 0$, then $F\to ...
5
votes
1answer
173 views

How can steel shavings get magnetized while hole tapping?

I was tapping a hole yesterday with my uncle into a piece of soft steel. (A tap cuts threads on the inside of a hole, to accept a machine screw or bolt.) The tap was NOT magnetic! As I finished boring ...
1
vote
1answer
389 views

Proof that the ground pushes you up [duplicate]

It has been said that when you try to jump you are exerting your force on the ground and the ground pushes you up. I was wondering if this was an over-simplification or not. If so, what's the full ...
0
votes
1answer
183 views

Why are there usually grids in front of sound speakers?

Usually, the sound speakers have this metal grid. However, not all of them have this. Is there any purpose, maybe related to the sound quality, that justifies this? Or is it only for physically ...
-1
votes
1answer
86 views

Perceived sway difference between double-decked vs. single-decked buses?

Why is that when I'm standing in a moving double deck bus, my body doesn't move a lot; whereas, in a moving single deck bus, my body moves quite a bit? It seems like I swing a lot in single deck ...
9
votes
1answer
176 views

Why can movies get away with 24 frames per second, but games can't? [closed]

Movies look reasonably smooth at 24 frames per second; unless the screen is huge and you use your peripheral vision, you usually can't see each frame individually. This has lead to a large amount of ...
1
vote
1answer
299 views

Will the “Vacuum Wine Saver” suck the bubbles out of Champagne?

The "Vacuum Wine Saver" comes with the following "warning": Not for sparkling wines Intuitively and naively, I imagine that the bubbles (or the "bubble-potential"—my made-up terminology) will be ...
10
votes
3answers
172 views

Milky Way Voyeurism

When and where on earth do we get the best view of the Milky Way? I believe it helps if it is night if it is winter to look in the direction of the galaxy center I think that this information ...
5
votes
5answers
648 views

Why is it easier to walk diagonally upstairs

Try it yourself on a set of wide steps! Work is given by $$\int_C \mathbf{F} \cdot d\mathbf{x}$$ where $C$ is a path integral. In this case I think $\mathbf{F}$ is a rotational vector field because ...
13
votes
5answers
11k views

Do low frequency sounds really carry longer distances?

It is a common belief that low frequencies travel longer distances. Indeed, the bass is really what you hear when the neighbor plays his HiFi loud (Woom Woom). Try asking people around, a lot of them ...
60
votes
12answers
9k views

Why are radiators always placed under windows?

I don't know if anyone else has noticed this but in most buildings and most rooms, radiators are predominantly placed under a window. Now, in my eyes, that is the worst place to put them; hot air ...
1
vote
1answer
137 views

Experiment regarding myopic correction by a manipulation of fingers?

Here is a small experiment my tutor once told us for just amusement. It works for myopic people at least, and can be a good check to see if you have myopia. With your naked eye, ("remove the ...
0
votes
2answers
139 views

How do you keep a fridge full of food cooler?

I just graduated and a mate moved into a flat (none of us are physicists by the way). So, were graduates, we got a new flat, and were broke. So, were now having a debate on how to keep a fridge ...
0
votes
1answer
48 views

Are there anti entropic agents [duplicate]

The entropy of an isolated system always increases, Considering an intelligent actor in the system who can organise different objects in the system, doesnt the measure of disorder reduce albeit for ...
54
votes
3answers
6k views

Why can we see the dust particles in a narrow beam of light (and not in an all lighted area)?

Let us say that I am sitting in a room with all the drapes open. Bright sunlight is coming through the window. The whole room is brilliantly lighted. I will not be able to see the dust particles ...
1
vote
2answers
314 views

The Soda Can and air pressure experiment

Yesterday, I made an experiment. I filled an empty (but contains air) soda can with a little bit of water. Then I turn on fire at the sides of the soda can so that the water starts boiling. Next, I ...
5
votes
1answer
168 views

Boiling noodles

Last week I did an expermient which goes as follows, I boiled some amount of water, and then put in a small piece from an uncooked thread of noodle, first of all it went right down to the bottom of ...
1
vote
1answer
321 views

The physics of the deodorant spray bottle volume

I noticed that deodorant (or anti-transpirant) spray bottles (pressurized?) usually contain $150~\text{ml}$, max $200~\text{ml}$ (that I've seen; although I think I spotted some $300~\text{ml}$ on the ...
4
votes
2answers
263 views

Why do clouds appear black?

I have noticed clouds appearing black during rain. But I don't know what makes clouds to acquire that colour. This phenomenon doesn't appear every rainfall. There has to be distinction to white ...
3
votes
3answers
326 views

Why is gas(oline) in gas stations sold by volume (as opposed to mass)?

Fluids (including natural gasoline/petroleum) have variable volume based on the ambient temperature for the same mass of fluid. So, really, the amount of gas that you're filling your car with depends ...
1
vote
1answer
1k views

Where does the energy of a light bulb come from?

Where does the energy of a light bulb come from? Is it from the coil of wire, magnet in the generator, mechanical input to the generator or plug where the generator is connected to the wall?
0
votes
2answers
612 views

Punching - Force or Momentum?

If I want to punch a person inflicting maximum damage, what do I need to care about? My force of punching, i.e, do I need more acceleration? Or do I need momentum, i.e my velocity for punching?
1
vote
1answer
130 views

Surface Water Drainage - Grate Inlet Capcity

The situation is a grated drain across a driveway entrance (so a thin long drain) if I know the roughness of the upstream surface (ie mannings roughness), the slope of the surface upstream (which is ...
3
votes
1answer
126 views

How big an egg can be? [closed]

Please hold on to flag as off-topic. Few days ago I received a question - how big an egg can possibly big? Can it be as big as 1 meter, as a human? (Imagining that there could be really huge animals ...
1
vote
1answer
152 views

How does a roof top ventilator work?

I have spotted this on the rooftops of industries, workshops, etc. I guess this is used for providing ventilation. This is not electrically powered. But then how does this work??
5
votes
2answers
2k views

Why does deodorant always feel cold?

We all use deodorant and they always feel cold, why is that? Is it because it is liquid inside the bottle and a gas when it is released?
10
votes
4answers
844 views

How big should a lens of a telescope be so we can see the American flag on the Moon from the Earth's surface? [duplicate]

How big in diameter should the lens of the imaginary telescope to be so we can see the American flag from e.g. some observatory in Hawaii?
4
votes
2answers
241 views

Is it possible to trap smoke or a smoke like gas inside a glass bubble?

I am a glassblower, and I would like to trap smoke in a glass bubble, my hope is to create an infinitely lingering smoke inside. Is this possible?
1
vote
1answer
64 views

Tsunami : power of destruction [closed]

I'm not sure this is the good place to ask those questions. Sorry if it isn't. Are there studies that evaluated the resistance of buildings against tsunami ? What kind of buildings could manage a ...