# Search results

1. ### What decides the colour of light?

Consider a beam of light passing through a slab of some refractive index. We know that the speed and wavelength of the light changes, but its frequency remains the same. Since the wavelength of the light changes, does its colour change, or does it remain the same as its frequency remains the same.
2. ### Aerofoil Question

Without the engines, the plane can't fly. This is what I meant by that statement.
3. ### Aerofoil Question

Lines getting closer does indicate compressibility. Can you tell me what else can possibly indicate compressibility.
4. ### Aerofoil Question

This is turbulent because there is a change in pressure with space (the pressure does change as the air moves towards the foil). Turbulence does occur when you have variation of pressure with space and time. This is What actually happens in the case of an aerofoil (look at the second diagram).
5. ### Aerofoil Question

I just wanted to mention that point about turbulence because I wanted to say that Bernoulli's equation could not be applied
6. ### Aerofoil Question

HEY, you can see from the video that the lines are closer to each other on the top part of the foil than the ones on the bottom. Thus the pressure should be higher at the top if you do not consider the velocity part. Thus you can not say anything about the net effect (considering both the...
7. ### Aerofoil Question

The flow is of course turbulent, otherwise the velocities of air packets would not change. Think about it. I did not say that it is turbulent because of the curvature of a streamline.
8. ### Aerofoil Question

Bernoulli's equation does not apply to this kind of flow because the flow is turbulent. Bernoulli's equation applies only to those situations where the fluid is incompressible, which is clearly not the case from what the video shows.
9. ### Aerofoil Question

Your explanation is somewhat cyclic. You say that the pressure provides the force to accelerate the packet of air, and at the same time, the acceleration of the particle causes the change in pressure (because of acceleration, there is difference in velocities of the packets of air along S-T-E...
10. ### Aerofoil Question

Bernoulli's principle says that the air blowing along S-T-E must travel a path longer than than that travelled by air blowing along S-B-E, and for the time taken to reach E must be the same Sorry, I did not notice that I typed the words "Bernoulli's principle" in the beginning my question is all...

Thanks
12. ### How long can a wire be?

According to Einstein's theory, it would require infinite amount of energy to accelerate something to speeds greater than that of light. So, beyond a point, the thread would have to break, or the the other galaxy would slow down(if the thread was strong enough). If the second case somehow...
13. ### Aerofoil Question

Consider this aerofoil. Let the leftmost point be S and rightmost point be E. Let the topmost point be T and a point on the bottom of the foil be B. Let the wind blow as shown in the figure above. Bernoulli's principle says that the air blowing along S-T-E must travel a path longer than than...
14. ### Heisenberg's Uncertainty

Some time ago I saw a video relating the large hadron collider. They said that the particles could be accelerated to a velocity of 99.999% the speed of light and they also added that the measured velocities were to an extremely high degree of accuracy. They also showed where the particles...