why is friction in the opposite direction of the motion not always the case, when considering someone walking?
824753
For someone walking, it is STATIC friction that is acting, not KINETIC friction since the person's feet are not in motion relative to the ground while they are in contact with the ground (unless the person is slipping). So, in terms of the static friction, as a person walks, they are bushing backwards against the ground and the static friction is what is pushing against them, pushing them forward, so again it IS in the opposite direction to the force being applied.
570941
because so you don't change your balance centre a lot and abruptly, you don't have to adjust it as much as you shoudl when you walk normally which is useful when you have to pay attention to not losing balance completely
789370
Probably compensation for an unnatural move...it doesn't feel right, so your body tries to compensate for it.
511849
When a person walks slowly, very slowly, the upper limbs tend to swing in unison. Basically, what is happening here is that limbs swing forward to catch up with the forward movement of the body. Because the body is moving slowly, the limbs are actually moving faster than the body (that is because the limbs are accelerating through the force of gravity). When the limbs move ahead of the body, they have to swing back. So, the two limbs are moving back and forth like a pendulum. When a person walks at a medium to brisk pace, they tend to swing the upper limbs in a contralateral fashion with the lower limbs � that is right foot and left hand move together, while left foot and right hand move together. There are some experts that will tell you that this movement is being done for the purposes of balance, but I find that explanation to be unsatisfactory at walking speeds (it works a little better for running, but running is a completely different style of locomotion than walking). We can, after all, walk just fine without swinging our limbs, such as when we are carrying and object or when we make a conscious choice not to swing them. Similarly, when we carry an object in only one arm, the other arm tends to swing. One swinging limb would actually be harmful to balance, so in my opinion if arm swinging is important for balance during locomotion, you wouldn抰 swing your arms unless you could swing both of them. What I believe is happening is that arm swinging is a neurological holdover from quadrupedal locomotor patterns. When quadrupeds walk, most of them tend to do so with a contralateral gait pattern � which does aid their balance when moving at slow walking speeds. Human bipedalism is such a new evolutionary development, that the neural pathways that control locomotion have not yet faced selective pressures to change. So, when we swing our arms, our brain (or perhaps more appropriately the cerebellum) is controlling our limbs as if we where still quadrupedal animals.
772763
yes.because of the touching sense.if some one touch from behind we suddenly turning .is       not it?like that oly.
641452
opposite force being applied
540441
Depends on what friction we are taking into account:\n\n1)Friction from the road: The frictional force acts in the same direction as the diection of the movement of the bicycle, because it acts at the point of contact of the tyres and the road and at that point the movement of tyres is tangentially opposite to the movement of the bicycle, and thus the friction force always acts opposite henceforth it acts in the same direction of the movement of the bicycle.\n\n2)Friction from air: Air friction will act opposite to the motion of the bicycle.
54736
Check your movement configuration.
555212
Yes, velocity is changing it's direction as well as magnitude. Acceleration due to gravity is acting downward.
784822
According to Newton's first law of motion, a moving body travels along a straight path with constant speed (i.e., has constant velocity) unless it is acted on by an outside force.\n\nFor circular motion to occur there must be a constant force acting on a body, pushing it toward the centre of the circular path. This force is the centripetal (“centre-seeking”) force. The centrifugal (centre-fleeing) force will, therefore, be the opposing force which pushes away from the centre\n\nThe two forces are equal in magnitude and opposite in direction.
256564
Creates a lot of motion but doesn't take you anywhere?
863911
Because not everything is the same size & mass and going at the same speed, etc. Those attributes... vary.
845875
Ah, time to dig out the physics from last year.  If I remember correctly:\n\nStatic friction is when the force of friction is greater than the force applied; thus basically what amount of force it takes to move the object from rest.\n\nKinetic friction is when you apply a force for an object to keep sliding.  In this, it "breaks free" of your push and continues sliding.\n\nAnd the force needed to initially break the static friction (to get it moving) is much more than what is needed to keep it going.\n\nHope this helped a bit.  Just remember that static friction is associated with objects at rest and kinetic is objects in motion, and don't get the two mixed up. :*P\n\nHave fun with physics!
642435
It's simply because two negatives repel. But if they are moving in different direction then too they will repel if they are close enough, but it would be hard to notice as they would already be moving away.
785005
Because the shoe is on the other foot.
690572
against the direction of travel.
933078
You cannot get away from friction.  Material properties are also not going to be exact.