Physics Lover

By Akash Peshin One of the most beautiful things I’ve ever read in my life is that we are literally the remnants of stars. “The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars”, wrote Carl Sagan, concluding, “We are made of star stuff.” The Orion Nebula, one of our nearest star nurseries. (Photo Credit: peresanz / Fotolia) The elements that comprise life are the scattered ashes of stars after they suffer horrific, explosive deaths. So, in a way, they died so you could be born. However, not all elements in the periodic table were created in the core of a star. A few were created outside it, by nature, and the rest,  by us . Let’s first understand how some were created inside a core, which requires us to examine the life of a star. Natural Elements The lightest elements hydrogen and helium were created when the dust settled after the  Big Bang . A nascent star comprises mostly this ...

By Akash Peshin One of the most beautiful things I’ve ever read in my life is that we are literally the remnants of stars. “The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars”, wrote Carl Sagan, concluding, “We are made of star stuff.” The Orion Nebula, one of our nearest star nurseries. (Photo Credit: peresanz / Fotolia) The elements that comprise life are the scattered ashes of stars after they suffer horrific, explosive deaths. So, in a way, they died so you could be born. However, not all elements in the periodic table were created in the core of a star. A few were created outside it, by nature, and the rest,  by us . Let’s first understand how some were created inside a core, which requires us to examine the life of a star. Natural Elements The lightest elements hydrogen and helium were created when the dust settled after the  Big Bang . A nascent star ...

Mechanics velocity v̅  =  Δ s Δ t v  =  d s dt acceleration a̅  =  Δ v Δ t a  =  d v dt equations of motion v  =  v 0  +  at s  =  s 0  +  v 0 t  + ½ at 2 v 2  =  v 0 2  + 2 a ( s  −  s 0 ) v̅  = ½( v  +  v 0 ) newton's 2nd law ∑ F  =  m a ∑ F  =  d p dt weight W  =  m g dry friction f s  ≤ μ s N f k  = μ k N centripetal accel. a c  =  v 2 r a c  = − ω 2 r momentum p  =  m v impulse J  =  F̅ Δ t J  =  ⌠ ⌡ F   dt impulse-momentum F̅ Δ t  =  m Δ v ⌠ ⌡ F   dt  = Δ p work W  =  F̅ Δ s  cos θ W  =  ⌠ ⌡ F  ·  d s work-energy F̅ Δ s  cos θ = Δ E ⌠ ⌡ F  ·  d s  = Δ E kinetic energy K  = ½ mv 2 K  =  p 2 2 m general p.e. Δ U ...