What is Newtons third law of motion? If one object exerts force on another object, then the seccond object exerts a force of equal strength in the opposite direction on the first object. You can reduce the resistive force of sliding friction by applying lubrication between the two surfaces in contact, by using rollers, or by decreasing the normal force.
Friction, in simplest terms, is a force that opposes motion. It occurs when two surfaces are in contact with each other. Friction occurs due to the roughness of the surfaces in contact.
Even if a surface appears really smooth to our eyes, it is not so at micro scale or nano scale. Friction is a contact force when two surfaces interact.
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Factors That Affect Friction A number of factors affect the frictional conditions at the interface between these two surfaces in relative motion.
These factors are: Surface Finish — The number, roughness and even the directional contact points of the asperities on the surfaces can dramatically affect the frictional coefficient. Surface Interaction It is important to understand how two metal surfaces within a machine interact with each other. Related Articles. Ten Tips for Proper Bearing Maintenance. Featured Videos.
Atten2 S Oil Wear 2. Featured Whitepapers. Does water ingress have to be the end of your oil's life? Neural Network Detection of Machine Faults. Cement Industry Contamination Solutions. To reduce friction, oil is added to the engine.
The oil coats the surfaces of the moving parts and makes them slippery. They slide over each other more easily, so there is less friction. In some cases, friction is desirable while in other cases, friction reduces the effectiveness of machines.
Without friction, you would not be able to walk, the wheels on a vehicle would have no grip on a road surfacing and the vehicle would not be able to move forward. On the other hand, friction is undesirable in most of the cases.
Friction causes mechanical parts to seize and wear out. Activity 1: Take two pieces of paper. Wad one of the pieces of paper into a ball. Leave the other piece of paper like normal.
Hold the pieces of paper above your head. Drop the pieces at the same time. The wadded piece will fall to the ground immediately. The flat piece of paper will flutter down more slowly because it has more surface area to create friction or drag on the air as it drops. To begin, fill the bottle with rice. Try sticking the chopstick down into the bottle. When you grab the chopstick and pull up, what happens? The stick should just come right out.
How do you make the rice stick to the chopstick so you can just pick it up? You've got to add more friction. Here's how. Put the lid on the bottle and tap the bottom of the bottle on a hard surface. Do this a few times to compact the rice and get rid of the air pockets.
Now you should have room to add a bit more rice to the bottle. Once you've added a bit more rice, stick the chopstick back into the bottle. This time, when you pull up on the chopstick, you should be able to pick up the whole bottle.
Why does friction warm your hands when you rub them together? Outside wooden steps may get slippery when they are wet. How could you make them less slippery? Friction is the force that opposes motion between any surfaces that are in contact. Static, sliding, and rolling friction occur between solid surfaces. Fluid friction occurs in liquids and gases. Static friction acts on objects when they are resting on a surface. For example, if you are hiking in the woods, there is static friction between your shoes and the trail each time you put down your foot see Figure below.
Without this static friction, your feet would slip out from under you, making it difficult to walk. In fact, that's exactly what happens if you try to walk on ice. That's because ice is very slippery and offers very little friction. One example is the friction that helps the girls climb the rock wall in the picture above. Static friction keeps their hands and feet from slipping. Sliding friction is friction that acts on objects when they are sliding over a surface.
Sliding friction is weaker than static friction. That's why it's easier to slide a piece of furniture over the floor after you start it moving than it is to get it moving in the first place.
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