Why can't it do both? Friction resists slipping between surfaces. If there were no friction, the object would tend to slide outward. Friction prevents that slipping and in the process exerts an inward accelerating force which keeps the object moving in a circle.miri144 said:But I thought friction was supposed to resist motion, not accelerate objects.
To reword Doc Al's post, friction resists relative motion between surfaces in contact with each other. The surfaces may be accelerating or experiencing an external force (such as gravity on an inclined surface), but if there is sufficient friction, there won't be any relative motion between the surfaces.miri144 said:But I thought friction was supposed to resist motion.
Static friction is the force that resists the motion of an object when it is in contact with a surface and not moving. It is caused by the microscopic irregularities between the object and the surface, which create interlocking forces that prevent the object from sliding.
The direction of static friction for an object on a car in circular motion is always perpendicular to the direction of motion. This means that the force of static friction is pointing towards the center of the circular path, helping to keep the object moving in a circular motion.
The direction of static friction is affected by the speed of the car, the mass of the object, and the coefficient of friction between the object and the surface of the car. As speed and mass increase, the force of static friction needed to keep the object in circular motion also increases. A higher coefficient of friction means a stronger force of static friction in the same direction.
Yes, the direction of static friction can change if there is a change in the speed, mass, or coefficient of friction of the object or car. If the speed or mass increases, the direction of static friction will also change to keep the object in circular motion. Similarly, a change in the coefficient of friction will also affect the direction of static friction.
The direction of static friction is determined by the vector sum of all the forces acting on the object. The net force must be equal to the centripetal force required to keep the object in circular motion. Using the equations for force, mass, and acceleration, the direction of static friction can be calculated for a given situation.