# All Questions

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### Baseball innovation [on hold]

I am working on technology for pitchers that will go inside of a baseball and give feedback on the velocity of the baseball, the spin of the ball, the direction of the spin, and the acceleration. I am ...
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### A free jet of liquid (incompressible) strikes a wedge as shown in figure below [on hold]

A free jet of liquid (incompressible) strikes a wedge as shown in figure below.
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### For a velocity field u(x, t) r r in a fluid of density (x,t) r r , show that [on hold]

For a velocity field u(x, t) r r in a fluid of density (x,t) r r , show that
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### Use conservation of mass and Newton’s second law to obtain pressure coefficient and show that p2 > p1 [on hold]

Use conservation of mass and Newton’s second law to obtain pressure coefficient and show that p2 > p1
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### Equivalent Force from Pressure [on hold]

I am trying to find the force at a certain point of a plate due to some pressure. I have a picture below (terribly drawn, sorry) but basically I have two plates with hinges on one side and the plates ...
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### Ricci tensor of direct product of manifolds

Imagine I have a (Lorentzian) manifold with a metric $\left[ {\begin{array}{cc} g_{\mu\nu} &0\\ 0&g_{mn}\\ \end{array} } \right]$ Will the Ricci tensor be also block diagonal ...
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### Correlation between large-scale galaxy structure and CMB fluctuations?

During a relatively non-technical astronomy seminar the other day, the speaker displayed the famous WMAP full-sky image as an aid to describing what the CMB is, the scale of its fluctuations, etc. ...
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### What is the eastward deflection due to Coriolis force [on hold]

Suppose, an air parcel is at the equator, and it has a northward velocity of 10 m/s. Due to Coriolis force, what is the eastward deflection of the parcel when it reaches 30N. Please show full ...
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### Projectile Motion on an inclined plane [on hold]

There are two parallel planes, each inclined to the horizontal at an angle $\alpha$. A particle is projected from a point, midway between the two planes, such that it grazes one of the planes and ...
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### Do atoms of a surface excite to reflect the light?

How do surfaces reflect certain colours and absorb the others?
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### Centrifugal force for non uniform circular motion [on hold]

If a body is under non-uniform circular motion, will it experience or will there be any impact of centrifugal force on the body upon eliminating the centripetal force? update-sorry.the title of ...
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### 2 calculations on absorbed and exposure dose [on hold]

1-A beam of 4.5 Mev neutrons is directed at 0.03 Kg tissue sample. Each Second 1.5×10^6 neutrons strike the sample. If the relative biological effectiveness of these neutrons is 7.0 . WHAT ...
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### Send a signal from Earth to a planet billion light years away instantly [duplicate]

If light was infinitely fast, we could just send a light signal from Earth to the planet. But I was wondering, if we made a perfectly non-elastic rope as long as the distance between earth and the ...
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