77,841 reputation
178167
bio website ratsauce.co.uk
location Chester, United Kingdom
age 53
visits member for 3 years, 3 months
seen 4 mins 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.


2d
reviewed Edit Characteristic polynomial of a Matrix
2d
revised Characteristic polynomial of a Matrix
typo
2d
reviewed Close Is this picture of the universe valid?
2d
revised Distance travelled given velocity at various moments of time
Typo
2d
reviewed Approve suggested edit on Why don't the kinematic equations agree with calculating velocity one second at a time?
2d
answered Distance travelled given velocity at various moments of time
2d
reviewed Close Work done from force-extension graph
2d
reviewed Close Arrow of time and virtual reality
2d
reviewed Close Distance travelled given velocity at various moments of time
Apr
20
comment Begginer Physics - Interpreting displacement-time graphs
It looks more like 2.828427125 to me.
Apr
20
reviewed Close Centrifugal force for non uniform circular motion
Apr
20
reviewed Close electric fields - point charges
Apr
20
reviewed Close Begginer Physics - Interpreting displacement-time graphs
Apr
20
reviewed Reject suggested edit on Why does a bicycle come to rest after travelling a distance?
Apr
20
comment Force of gravity in the event horizon
The force goes to infinity at the event horizon. However nota bene that the force calculated here is coordinate dependant and its value is as observed from far outside the horizon.
Apr
20
comment Force of gravity in the event horizon
No, it's $$F=ma=\frac{GMm}{r^2}\frac{1}{\sqrt{1-\frac{2GM}{c^2r}}}$$
Apr
20
reviewed Approve suggested edit on Why does the comb attract the pieces of papers if they're neutral?
Apr
20
reviewed No Action Needed Why does the comb attract the pieces of papers if they're neutral?
Apr
20
comment How long would it take to get to Kepler 189f?
Hi John. We generally downvote questions we perceive to be from lazy students, though I'm guessing you're not a physics student so the downvotes are rather unfair. I've added a link to another question that asks basically the same question as yours. To calculate travel time you need to use the equations for an accelerating object, and you'll find these in John Baez's article. To calculate the travel time do the calculation for half the distance to the star at steady acceleration then just double the calculated time. This works for time on Earth and on the rocket.
Apr
20
comment How long would it take to get to Kepler 189f?
possible duplicate of Travel duration from earth to a star at 9.8 m/s² acceleration