Originally Posted by justme Is it correct to talk about momentum being transferred between objects during collisions? Did classical physicists view it this way at all?
I have heard the expression before and as a physics educator I want to make sure I am using the right language.
By describing momentum this way it seems to be modelling momentum as a "thing" that can be transferred or flow around a system, like "energy" being transferred. And that fact that it is conserved during collisions makes this language even more tempting to me.
However I have also heard that is not right to think of it this way at all, it is far better to just restrict its description to being a mathematical quantity (mv). |
I am very happy to discuss this, (and it leads to some deep Philosophy of Physics( but what sort of Physics are you a 'trainer' of, that you don't already have the answer?
Yes there was a time, before the word energy was invented, when one of the known types of energy was thought of as a substance, called caloric.
This view was later discredited.
Energy and momentum are properties of matter or substance, but they are not substances themselves.
But unlike mass, which is another property, you cannot 'transfer' a quantity of this property from one system to another.
Mass is a property that cannot be taken away from a body.
As to conservation laws it can be difficult to explain to beginners whether to use conservation of energy or conservation of momentum.
Iam am sorry to disillusion you, Oz, but you need Mathematics for this purpose.
Consider the following:
A rifle bullet of mass 0.1kg is fired at block of wood, of mass 1kg and situated on a long frictionless surface. The bullet impacts at 440m/s.
The impact embeds the bullet in the block and the two speed off at what velocity?
What is the kinetic energy before and after the impact?