jbriggs444's latest activity
-
jbriggs444 reacted to phinds's post in the thread B Conservation of kinetic energy in expanding space with
Like.
No, since energy is not conserved on cosmological scales, is just isn't there anymore. -
jbriggs444 replied to the thread B Conservation of kinetic energy in expanding space.The easy answer is that energy is not conserved in an expanding universe. The law of conservation of energy follows (via Noether's...
-
jbriggs444 reacted to Herman Trivilino's post in the thread B Understanding Newton's Third Law and the Net Force on Objects with Like.
FWIW the term action-reaction can imply that the action has some kind of different status than the reaction. As if one precedes the...
-
jbriggs444 reacted to Dale's post in the thread B Understanding Newton's Third Law and the Net Force on Objects with Like.
If you push an object then Newton’s 3rd law says there are two forces. One force acts on you and one force acts on the object (and they...
-
jbriggs444 replied to the thread A very naive encryption scheme : How would an expert crack it?.This original series of digits. Is it finite? If the original key is finite then one should instead use a cryptographically strong...
-
jbriggs444 replied to the thread B Interstellar asteroids.Sure can. I have no reason to be very confident in my numbers. We have ##F = \frac{mv^2}{r} = \frac{Gm^2}{r^2}## where ##F## is the...
-
jbriggs444 replied to the thread Problem with pulleys - two fixed and one movable.You have assumed that the left hand mass ##m_1## and the right hand mass ##m_2## accelerate downward at the same rate, ##a##. What if...
-
jbriggs444 replied to the thread B Interstellar asteroids.That clarification was in #6:
-
jbriggs444 replied to the thread Reconcile poundforce w/slug and lbmass.By the time I went to high school seven or eight years later the science classes were teaching nothing but MKS (or cgs). Like @Mister T...
-
jbriggs444 reacted to Herman Trivilino's post in the thread Reconcile poundforce w/slug and lbmass with Like.
No. There is no officially-sanctioned definition of the pound-force. The definition of the pound Avoirdupois is 0.453 592 37 kg. The...
-
jbriggs444 replied to the thread B Conservation of kinetic energy in expanding space.One can define the kinetic energy associated with peculiar movement relative to a co-moving coordinate system. In an expanding universe...
-
jbriggs444 reacted to Bandersnatch's post in the thread B Conservation of kinetic energy in expanding space with Like.
As I see it, the poster is asking about an effect opposite to objects in expanding space asymptotically joining the Hubble flow over...
-
jbriggs444 replied to the thread Reconcile poundforce w/slug and lbmass.I love it when a discussion ends in agreement. One reason that many of us prefer to work with SI (the metric system) is to avoid unit...
-
Thank you. I had completely forgot about this constant. I have thermo txt enroute which will supply plenty problems of lb steam into...
-
jbriggs444 replied to the thread Reconcile poundforce w/slug and lbmass.As I pointed out in your other thread, the correct formula for systems of units that are not coherent is ##F=kma## where k is a unit...