143,715 reputation
13244402
bio website ratsauce.co.uk
location Chester, United Kingdom
age 54
visits member for 4 years, 6 months
seen 2 hours ago

Semi retired old time computer nerd who started programming on a Commodore Pet.

Since I'm also active in the Physics forum I should add that I started as a theoretical chemist, moved into solid state photochemistry and finally worked in industry as a colloid scientist. I only became a full time computer nerd in 1997.


1d
reviewed Leave Closed Would a piece of paper look as big as a small bedroom to an atom?, or bigger?
1d
reviewed Leave Open definition of Hamiltonian in statistics
1d
comment What is extension produced in spring?
Hi Prasenjeet and welcome to the Physics SE! Please note that this is not a homework help site. Please see this Meta post on asking homework questions and this Meta post for "check my work" problems.
1d
comment Point of getting each other after chasing!
Hi Michaele and welcome to the Physics SE! Please note that this is not a homework help site. Please see this Meta post on asking homework questions and this Meta post for "check my work" problems.
1d
reviewed Leave Closed Commutation relation between linear momentum and vector Potential
1d
reviewed Reviewed Induced voltage by dropped magnet?
1d
reviewed Close Quantum Entanglement - How To Interpret
1d
reviewed Close When we ride a bicycle, why do we tend to move left when we turn it right?
1d
comment Are there any benefits from doing Physics MCQs without a given answer key?
Hi Larry. I also find it frustrating when books don't give answers. However for many well known books you'll find answers on the Internet. Try Googling for the text in the question.
2d
reviewed Reviewed Pressure change with a pipe diameter change
2d
comment variation of electrostatic potential on moving radially outwards from the nucleus of an atom
@Abhirikshma: I don't have electron density data to hand, but outside the atom the potential will be close to zero, in the outer reaches of the atom it will go as $1/r$ and near to the nucleus it will go as $Z/r$, where $Z$ is the nuclear charge. In between it will transition smoothly between those two limits.
2d
reviewed No Action Needed Why can't we see light travelling from point A to B?
2d
comment Area under v-t and a-t graphs
In that case you're correct, the area under the graph does not equal the change in magnitude of the velocity.
2d
reviewed No Action Needed Calculate speed from accelerometer
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reviewed No Action Needed Crash course on algebraic geometry with view to applications in physics
2d
comment Area under v-t and a-t graphs
The graph of $a:t$ that you describe is a horizontal straight line i.e. constant acceleration, so the area under it will be $at$ giving us the equation $\Delta v = at$ or in the form it's more commonly taught to schoolchildren $v = u + at$. This correctly describes what happens to the thrown ball because the velocity changes from $+u$ when you throw the ball to $-u$ when it lands, giving a change of $2u$ not zero.
2d
answered Pressure change with a pipe diameter change
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comment Using Lagrangian to get the equations of motion
Hi and welcome to the Physics SE! Please note that this is not a homework help site. Please see this Meta post on asking homework questions and this Meta post for "check my work" problems.
2d
comment What maximum theoretical speed can reach spaceship with EM Drive in space?
The EM drive doesn't work, so the maximum speed is zero. In the studies you link the measured thrust is so small it could easily be an unsuspected systematic error. No-one has unambiguously demonstrated thrust from an EM drive.
2d
comment Area under v-t and a-t graphs
The area under an acceleration-time graph does give the (change in) speed, in exactly the same way that the area under a velocity-time graph gives the (change in) distance. In both cases the area is equal to the intergral of the acceleration/velocity wrt time.