Friction between two stacked objects

• Panphobia
In summary, the conversation discusses the presence of friction between two stacked objects and how it affects the forces and accelerations in a given system. It is important to consider the conditions of equilibrium and whether the objects are in motion or not. The magnitude of friction remains the same in both cases due to Newton's third law.

Panphobia

There is friction in between the two stacked objects, but no where else.

Now what I was wondering was when I draw the fbd for the 6 kg square, there is a frictional force in left direction, but is the magnitude of it m1g*coefficient of friction, so (4)(9.8)μ?

This depends on the hanging mass. If they are in equilibrium (not moving) then I would say you are correct. Otherwise you would need to take into consideration the accelerations.

Panphobia said:

There is friction in between the two stacked objects, but no where else.

Now what I was wondering was when I draw the fbd for the 6 kg square, there is a frictional force in left direction, but is the magnitude of it m1g*coefficient of friction, so (4)(9.8)μ?

What is the mass of the hanging ball?

for fbd for 6kg mass, there would be normal forces from floor and mass m1, weight and friction whose direction is towards the left in your situation. the direction is independent of weight of ball. But magnitude depends on it. if its accelerating or on the verge of moving, then you are correct because you have used the condition for max friction. But if the objects are in equilibrium, then friction could range from 0 to max value depending on the mass of hanging weight.

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Legaldose said:
If they are in equilibrium (not moving) then I would say you are correct. Otherwise you would need to take into consideration the accelerations.
it should depend on the conditions of equilibrium, the answer should be correct only if the block is on the verge of moving. And even considering the acceleration, if there is any, answer should be right given that coefficient of friction doesn't change. Only tension should change for different accelerations. what do you think?

1 person
I was saying what was weird is that I have to incorporate friction twice, once on the top object and once on the bottom object, and this is kinetic friction "Legaldose", not static friction. Also the system IS accelerating to the right or down.

Panphobia said:
I was saying what was weird is that I have to incorporate friction twice, once on the top object and once on the bottom object, and this is kinetic friction "Legaldose", not static friction. Also the system IS accelerating to the right or down.

it is not at all weird...it is a consequence of Newton's third law

so the magnitude of this friction is the exact same in both cases correct?

Panphobia said:
so the magnitude of this friction is the exact same in both cases correct?

yes, exactly

I KNEW IT :D, just wanted to make sure I was doing it right :)

Panphobia said:
I KNEW IT :D, just wanted to make sure I was doing it right :)

great then, glad I could help!

1. What is friction between two stacked objects?

Friction between two stacked objects is a force that resists the motion or movement between the two objects when they are in contact with each other.

2. What causes friction between two stacked objects?

Friction is caused by the irregularities on the surfaces of the two objects that are in contact with each other. These irregularities create an interlocking effect, making it difficult for the objects to slide over each other smoothly.

3. How does the weight of the stacked objects affect friction?

The weight of the stacked objects does not directly affect the amount of friction between them. However, it can indirectly affect it by increasing the force of the objects pressing against each other, thus increasing the friction force.

4. How can friction between two stacked objects be reduced?

Friction can be reduced by using a lubricant or a smooth surface between the two objects. This creates a layer that reduces the contact between the two surfaces, making it easier for them to slide over each other.

5. How is friction between two stacked objects beneficial?

Friction has many practical uses, such as helping us walk without slipping, enabling tires to grip the road, and allowing us to hold objects without dropping them. In some cases, friction can also generate heat, which is useful in machines and processes such as braking or starting a fire.