2. Distinguish between the static friction and dynamic friction ?
3. What is limiting friction ? State the laws of limiting friction ?
4. How is rolling friction caused ?
5. Under what conditions the rolling friction increases?
Answers
Answer:
Static friction is a self-adjusting force because it comes into play when the body is lying over the surface of another body without any motion. ... When that body overcomes the force of static friction, the maximum value of static friction is reached -which is known as limiting friction.
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2) Static friction is what keeps the box from moving without being pushed, and it must be overcome with a sufficient opposing force before the box will move. Kinetic friction (also referred to as dynamic friction) is the force that resists the relative movement of the surfaces once they're in motion.
3) The force of limiting friction between two surfaces in contact is independent of the area of contact. Limiting friction is directly proportional to the magnitude of normal reaction N between two surfaces in contact, i.e. where n is constant of proportionality and known as coefficient of friction.
4) Rolling friction takes place when an object rolls on the surface. Sliding friction takes place when two surfaces are rubbed against each other. Rolling friction takes place due to the deformation of surfaces. Sliding friction takes place due to interlocking between microscopic surfaces.
5) Rolling friction increases when the surface is rough and the object to be rolled is heavier. Rolling friction increases if the area of contact increases, the surface is rougher and the object is heavier
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