High School Question about Friction

In summary: If the coeficient of friction is 0, than I don't need any force to push it?If it is .5, I only need to push 50% of it's total vertical force?I think I got this right.Which is why sliding is sometimes more efficient than lifting, right?If something had a coeficient of 1.5, you are better off lifting it off the ground.The friction coefficient is not the percent of force which is resisted, it's the ratio between the force between object/ground and friction.
  • #1
JasonRox
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If the coeficient of friction is 0, than I don't need any force to push it?

If it is .5, I only need to push 50% of it's total vertical force?

I think I got this right.

Which is why sliding is sometimes more efficient than lifting, right?

If something had a coeficient of 1.5, you are better off lifting it off the ground.
 
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  • #2
The friction coefficient is not the percent of force which is resisted, it's the ratio between the force between object/ground and friction.

For example, you know that gravity accelerates everything downwards at 9.8 m/s^2 so if we had a 5 Kg block sitting ona surface with a coefficient of 2:

Friction = Fn * u
Fn = -Fg
Fg = -9.8*m
Friction = -Fg * u = --9.8*m*u = 9.8*5*2 = 98 Newtons

So if you push the block, you need to push with more than 98 Newtons to accelerate it.
 
  • #3
"The friction coefficient is not the percent of force which is resisted, it's the ratio between the force between object/ground and friction."

But that's what Jason Rox said: " 50% of it's total vertical force?"

Essentially, yes, in order to keep something moving at a constant speed on a horizontal surface, you must apply a force equal to the friction force which is the friction coefficient times the "total vertical force".
 
  • #4
I doubt you'll ever come across a pair of surfaces with mu = 1.5.
 
  • #5
It's been awhile, but in the end, because frictional force rarely goes above it's vertical force, everyone chooses to slide big objects.
 
  • #6
  • #7
It is possible, but it is unlikely.

Friction exists because surfaces are uneven if you look REALLY close. You see little bumps, which the object must overcome to slide across the surface.

So if the surface consisted of walls, like a maze, it would be quite difficult to slip a television through without going around the walls. In the end, the bigger the bumps, chances are the coeficient of friction is higher.
 
  • #8
Try putting two pieces of glass on each other...

cookiemonster
 

What is friction?

Friction is the resistance that occurs when two surfaces rub against each other. It is caused by the microscopic irregularities on the surfaces and the force of the molecules interacting with one another.

How does friction affect objects?

Friction can either increase or decrease the speed of an object. For example, it can slow down a moving object due to the resistance it creates, but it can also help an object stay in place by providing grip.

What factors affect the amount of friction between two surfaces?

The amount of friction between two surfaces depends on the force pressing the surfaces together, the roughness of the surfaces, and the type of material the surfaces are made of. The greater the force and roughness, the greater the friction.

How can friction be reduced?

Friction can be reduced by using lubricants, such as oil or grease, between two surfaces. These substances create a layer between the surfaces, reducing the contact and therefore the friction. Smoother surfaces can also help reduce friction.

What are some practical applications of friction?

Friction has many practical applications, such as providing grip for tires on the road, allowing us to write with a pen, and creating heat when we rub our hands together. It also plays a crucial role in machines and technology, as proper friction allows for controlled movement and prevents slipping.

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