# All Questions

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### Gravitational entropy

In the beginning (big bang), mass was evenly distributed (if you consider an elementary particle as an extended object, like a circle on a very thin cylinder, with a radius near the Planck length, but ...
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### How to find the force of a magnetic field, resolving the components?

So, in answering this question the book resolves the components of the Force vector in this manner; (1) dFx= dF*$\sin \theta$ (2) dFy= dF*$\cos \theta$. And then, it integrates from $\theta_0$ to ...
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### Is static friction the only force causing a car to move (without sliding)?

A car is moving without sliding means that the friction between wheels and the ground is static friction. This is the force causing an object to move forward, therefore, its direction is the same as ...
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### Spring pendulum system [on hold]

Find the Lagrangian and the equations of motion for the system described by the figure using the Lagrange multipliers method. The mass $m$ can slide frictionless along the massless rigid rod of the ...
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### Why can't the wave model for radiation cannot account for the photoelectric effect?

While I understand the effect of varying wavelength and frequencies on the photoelectric effect, I can't seem to turn my mind around that question... I suspect it has to do with quantas and the non ...
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### Thermofluid mechanics inclined plane

As shown in the attacked image, a tank has an inclined wall at an angle of 450 to the horizontal. On this wall, there is a 1m square door that is hinged at A and has a simple latch at B. The distance ...
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### Components of gravity in an inclined plane

The reason the block accelerates down the inclined plane is that the resultant of $N$ and $mg$ acts down the incline. However, why is the force causing the block to accelerate down the incline often ...
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### Why does a ball eventually stop?

I was wondering, if the force of friction with the ground does not make any work on the ball and just give it the necessary torque to rotate (hence the consideration of static friction coefficient in ...