Is friction a force

1. According to the law of conservation of mechanical energy, the condition of conservation of mechanical energy is that the system only has conservative force to do work, only carries out the transformation between kinetic energy and potential energy, and the mechanical energy remains unchanged. Therefore, for a particle, if it meets the condition of mechanical energy, neither external force nor conservative internal force does work, neither external force nor conservative internal force does work for a particle

2. Wind, air resistance, friction are all forces. If you go against the wind, you will be slow; if you go with the wind, you will be fast.

3. In physics class, friction is a kind of force between two non smooth objects which contact and move relative under the action of force. It is opposite to the moving direction of the object and belongs to the category of reaction force; Resistance generally refers to the force (opposite to the direction of motion) that hinders the movement of an object; Friction resistance generally refers to the result of friction on the movement of objects
give an example to help understand: AB two non smooth objects stacked together, a in a non smooth plane, under the force F to push a, AB at the same time forward for uniform motion. Analysis: the force between a and plane, a to B, B to a
obviously: between a and the plane, the plane proces friction force on a, which constitutes the friction resistance of a movement, the magnitude of which is equal to the force F, and the direction of which is opposite; The friction force ABF makes b move forward in the same direction as the force F, and its magnitude is equal to the friction force B exerts on a; The friction force BAF is equal to that of ABF, but opposite to that of ABF.

4. Friction is a kind of force.

5. According to Newton's first law, an object always remains stationary or moving in a straight line at a constant speed until an external force changes it
when an object is at rest, it is pulled by a pulling force. With the increase of the pulling force, the friction of the object increases (two forces balance). When the pulling force is greater than the maximum static friction, the object will move. (because the dynamic friction is less than the static friction, strictly speaking, the object will accelerate, the acceleration = (pulling force dynamic friction) / M)
when the object is in motion, If there is no tension, the object will decelerate under friction until the speed is zero. If a pull force opposite to the friction force is applied when the object is moving, then if the friction force is equal to the pull force, the object will move at a constant speed (because the resultant force is zero)
if the object is only affected by the pull force and friction force, and the pull force is equal to the friction force, and the two forces are opposite in direction, which is a pair of balanced forces, then the object is in a state of equilibrium, At this point, it is static or doing uniform linear motion

6. No matter
F = UN, the size of N and G is not necessarily related under different contact forms and different states, but it may also happen that the friction force is equal to gravity.
if you are talking about a general object placed on a horizontal plane, the friction force must be less than gravity. N = g, u & lt; one

7.

It's the motivation. When people walk, they push their feet backward to proce static friction, which is the driving force. Static friction is different from the force on the ground, so it is not a balanced force, so there is no problem of size

< H2 > extended data:

when an object slides on the surface of another object, friction between contact surfaces hinders their relative motion, which is called sliding friction. The sliding friction is related to the roughness of the contact surface and the pressure. The larger the pressure is, the rougher the contact surface is, and the greater the sliding friction is

8. So to speak. Friction is proced by the contact between two objects, so there must be force and supporting force.

9. Considering that you are a sophomore in junior high school, don't worry, take your time to see that
force is the reason that makes the movement change, not the reason to maintain the movement

any object can keep its motion state unchanged without force, inertia

the friction is too small to walk. That's because when you take this step, you need to start moving from static, so you need the support of force. Here, friction is the driving force

the difference between sliding friction and static friction. For example, if you take a board to wipe the blackboard, the static friction is between your hands and the eraser, and the sliding friction is between the eraser and the blackboard. In short, if two objects begin to rub against each other, it is sliding friction; If it's still stuck together, it's static friction

the direction of sliding friction depends on which of the two objects you are studying. In short, it is opposite to the movement direction of that object

hope it can help you. Students like you who like to ask questions will surely learn physics well in the future. Come on

10. Your understanding is correct. When the static friction reaches the upper limit, the friction will change