- physics
- eli5
- Newtons second law
- If we imagine ourselves in empty space. We place and object in this space. If the ball was
falling, it remains falling, if its resting on something it stays at rest. We notice in
nature that objects have an interaction between them causing each object to change its
motion. Inertia is this idea that the object in free space will not doing anything
outside its current state unless its acted on by a force. What Newtons second law
describes then is how to we determine the magnitude of some interaction on the object (if
there were to be one). We notice that objects have varying degrees on ease in switching it
from its current state to a new interacted (by a force) state. We call this degree of
difficulty mass.
- So now that we notice theres a property of the object that directly impacts the
interaction process. What else comes into play in determining the interaction? Because we
are describing motion (the effect of the interaction) there is a degree of motion that
happens. So we have the inability to move the object from its current state mass and to
what degree we deviate that motion. Are these all the variables required in determining a
magnitude for interaction? According to Newton, yes.
- The force varies with a new property of the object then. Its mass and motion. If we were
define how much we want to change the objects motion we could say. Change its current
velocity from v to v′ whether thats a deviation in path (resulting in velocity
vector changes) or a speeding up and slowing down on its current path we need to know the
change we’re looking for. To get the most accurate force we want this v′−v=δv get this change over the smallest epoch. To do this we use calculus. The
change in velocity then is actually acceleration. With all this we can say the interaction
needed on an object of a mass m to move it from its path to new velocity v is proportional
to the mass times the acceleration. The factors used in determining this are tightly
constrained buy speed and distance and a new property mass which is fundamental to
variation in the force.
- So we want to change the objects acceleration by this much but must take into account the
difficulty of this by scaling it by mass. So the higher the mass, the more force required
to achieve a given change in velocity.
- motion of the mass