friction
The natural tendency of an object to not move (if it wasn't moving), or to keep moving (if it was moving). Inertia is the characteristic that a object will want to stay at rest or in motion. You can feel this in a buss when it suddenly moves this is why you get sent backwards.
Newton's Third Law of Motion states that bodies simultaneously exert force on each other. Some examples of this law are standing, a bird flying, and a car moving down the road.
Friction will always act in the direction opposite of the relativistic motion of two objects. If object A is moving to the right on object B, then object A will experience the friction to the left. However, object B will be moving to the left on object A and will therefore experience the friction acting towards the right.
If you apply force to an object, you accelerate it. If you apply the force in the direction that the object is moving, you speed it up. If you apply it in the opposite direction, you slow it down. If you apply the force in another direction than the object is moving in you will change the direction of the objects motion. The amount of acceleration is given by a = F/m where a is acceleration, F is force and m is the mass of the object.
Energy. Potential energy is like stored energy: ready-to go. (a cart at the top of a roller coaster hill has a lot of potential energy) Kinetic energy is moving energy: in-motion. (when that cart goes speeding down the hill)
friction
Friction always want to retard the motion of a moving object. So friction slows down and finally stops a moving object.
friction stops things from moving and slows it down
According to Newton's first law of motion, an object that is in motion will stay in motion. Basically if an object is moving, unless something stops or alters its path in any way, the object will continue to move down the same path.
Forces are pushes or pulls. They can start objects moving, they can stop,speed up, slow down, or change the direction of moving objects. They can lift things, or cause them to turn, bend or twist. They can also prevent motion; eg. a handbrake on a car stops it from rolling down the hill.
The object slows down and eventully stops.
It resists the motion (slows it down)
It resists the motion (slows it down)
by moving them up and down in a chewing motion
What happens to pieces of rock that are carried along by wind, moving ice, or moving water? A fast wind eventually slows down. A glacier stops moving and eventually melts at its front end and sides. All streams eventually slow down and end when they flow into a large body of water, such as a lake or ocean. When water stops moving, it also stops moving, it also stops carrying along bits and pieces of rock are dropped
This is an interesting point of Newtonian physics, because it requires you to look at the world a different way. Our normal experience is that when something is in motion, it only moves for a certain period of time, then it slows down and stops. No matter what it may be, whether a spinning top, a thrown ball, a falling rock, whatever, everything comes to a stop, sooner or later. Newton's insight is that motion does not just evaporate, it doesn't disappear of its own accord, motion stops because something stops it. Things stop moving because there is some kind of friction or other force which opposes that motion. Whereas, when an object is moving in an environment in which there is no force opposing that motion, it will just keep moving. Inertia is that property which allows motion to continue. Inertia does not just dissipate, it remains, until some other force counteracts it. That is why we say that an object in motion will tend to remain in motion. It does have that tendency, even though in our normal experience, other factors are going to overcome that tendency.
It depends on what body part is moving - you will have to ask your question about a specific motion such as raising your arm or sitting down or whichever movement you are thinking of.