I sometimes wonder, what is real and what is a concept in physics: is that force , energy, ...?
There are often two ways to solve physics problems: one describing the problem with forces, the other reasoning with energy. So they look like the two faces of the same coin. Hence the question: which one is actually real?
Some quick arguments for and against
Energy:
+ converts between mechanical, chemical, thermal, radiative types, and even mass
+ quantum particles, when interacting, exchange energy
- looks like an integrative quantity (in the sense of mathematical integral)
Force:
+ feels very real, when you receive a ball in your face
+ we talk of fundamental forces, not fundamental energy
+ explains momentum, deformation well
- my physics teacher used to say "nobody ever saw a force"
- force is undistinguishable with acceleration
- at the quantum level forces are actually particles interacting
- at the quantum level, the uncertainty principle makes the newtonian force pointless (pun?): seems like we could know the vector's origin or the direction but not both
There are often two ways to solve physics problems: one describing the problem with forces, the other reasoning with energy. So they look like the two faces of the same coin. Hence the question: which one is actually real?
Some quick arguments for and against
Energy:
+ converts between mechanical, chemical, thermal, radiative types, and even mass
+ quantum particles, when interacting, exchange energy
- looks like an integrative quantity (in the sense of mathematical integral)
Force:
+ feels very real, when you receive a ball in your face
+ we talk of fundamental forces, not fundamental energy
+ explains momentum, deformation well
- my physics teacher used to say "nobody ever saw a force"
- force is undistinguishable with acceleration
- at the quantum level forces are actually particles interacting
- at the quantum level, the uncertainty principle makes the newtonian force pointless (pun?): seems like we could know the vector's origin or the direction but not both