Hello, nice to meet you all.
I'm self studying physics at age 18, and new to physics.
My greatest passion had been for mathematics, but I found there're many things to enjoy in physics too.
I delveloped my blog website to post notes about physics and mathematics which is not currently running...
I have a question understanding the reasoning in the book.
The book says in one dimension F=-dU/dr(p.185). From this, the system is stable at distance a when U'(a)=0 and U''(a)>0 where U is differentiated with respect to r.(p.217)
My question arises from the instance of a pendulum where a...