So I think I am confusing myself about forces. I know that when something is sliding down a ramp that it will have the force of gravity, normal force and force of friction acting on it.
But for an example, what if I had a toy cart and added a chocolate bar to it. When it is sliding down the ramp, the forces acting on it will be the force of gravity, normal force, friction but would there be an applied force on the toy cart from the chocolate bar?
Or would I just treat this still as "one system" and make it so that when I am calculating the forces I increase the mass to take into account the chocolate bar? Or would I have to put an applied force downwards?
Best Answer
For sure the object you will put in cart will act as one body until and unless they both have same velocity or I say that they both move relatively and this is possible if both have contact with each other. And if you want to take internal forces then you have to work on that but besides everything of what you ask the answer is simple that you have to take that as single body.
Example-
Let us say one block sliding down and for the sake of question and imagination let us take one small section of (red portion in image) as chocolate bar. So by seeing the FBD we can recognize that it will act as one body (as the red section is already a part of that block) will work as one system and it will act just same in your Cart example due to which the mass of the system increases.