Friction on top of object with frictionless surface?

In summary, the friction between the objects is insignificant and the boxes will move with the applied force.
  • #1
lax1113
179
0
Friction on top of object with frictionless surface?

Homework Statement


If an object1 has friction between it and object2, and object 1 rests on object 2, when a force is appliced to object 1 that is horizontal, what impact will it have on object 2 when the surface object 2 is on has negligible friction.



The Attempt at a Solution


This isn't the exact problem, but this is the part that i cannot understand. According to the answers in the back of the book, object 2 seems to be experiencing a force that is equal to that of object 1, minus the static friction. Whereas object 1 uses the kinetic friction to get its net force. I don't understand why this would be, if it even is.
 
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  • #2


The second object will move with the first object as long as the force applied does not exceed the force due to static friction between the objects.
 
  • #3


So, what about the case of one object having a different acceleration than the other object? Say the top one accelerates at 6m/s^2 and the bottom only 1m/s^2. Is this due to the fact that the bottom one has no actual force acting on it but just is being acted on by the friction of the top one?
 
  • #4


lax1113 said:
So, what about the case of one object having a different acceleration than the other object? Say the top one accelerates at 6m/s^2 and the bottom only 1m/s^2. Is this due to the fact that the bottom one has no actual force acting on it but just is being acted on by the friction of the top one?

No, the only way these can accelerate at different rates are if the force applied is greater than the force due to static friction between the blocks. If this happens, the top object will accelerate with respect to the bottom block and will end up falling off of the front.

[tex]\sum F_{top}=F_a-F_f=m_{top}a
\sum F_{bottom}=F_f=m_{bottom}a[/tex]

Something like that.
 
  • #5


I got you slight,
Thanks,
It is like the second example you gave, the acceleration is only for that moment in time, so after a while, the top would fall off of the bottom.

How do you make the white part? where you write stuff out...
Would help a lot when i try to explain stuff haha
 
  • #6


lax1113 said:
I got you slight,
Thanks,
It is like the second example you gave, the acceleration is only for that moment in time, so after a while, the top would fall off of the bottom.

How do you make the white part? where you write stuff out...
Would help a lot when i try to explain stuff haha

The coefficient of static friction that would hold the boxes together is equal to the force applied for all times except the initial push that sets it into motion and when the static force turns into kinetic friction and the top box accelerates off of the bottom. And you can put tags using the sigma icon in the create-a-thread box.
 
  • #7


Thank you very much!
Although I intially needed help with this problem, I think that the insert box might be even more helpful! I can never post questions here because it is so hard to understand with all the ^n and parenthesis everywhere.

Thanks!
 

1. How does friction on top of an object affect its movement on a frictionless surface?

Friction on top of an object can greatly impact its movement on a frictionless surface. The friction between the object and the surface can slow down or even stop the object's movement, as it creates resistance against the object's motion. This can cause the object to slide or roll less smoothly on the surface.

2. Can friction on top of an object completely prevent it from moving on a frictionless surface?

While friction on top of an object can significantly impede its movement on a frictionless surface, it cannot completely prevent it from moving. This is because the friction force is dependent on the weight and surface area of the object, and on a frictionless surface, there is no normal force pushing back against the object to create friction.

3. How can the coefficient of friction on top of an object affect its movement on a frictionless surface?

The coefficient of friction on top of an object can greatly impact its movement on a frictionless surface. A higher coefficient of friction means there is more resistance between the object and the surface, resulting in slower or more difficult movement. On the other hand, a lower coefficient of friction would allow for smoother movement on the surface.

4. Is there a way to reduce the friction on top of an object on a frictionless surface?

One way to reduce the friction on top of an object on a frictionless surface is by using a lubricant such as oil or grease. These substances can create a thin layer between the object and the surface, reducing the amount of friction and allowing for smoother movement.

5. How does the weight of an object affect the friction on top of it on a frictionless surface?

The weight of an object can greatly impact the friction on top of it on a frictionless surface. The heavier the object, the more normal force is created between the object and the surface, resulting in a higher friction force. This can make it more difficult for the object to move smoothly on the surface.

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