Friction Forces Between Stacked Blocks: Determining Direction

In summary, the conversation discusses determining the direction of friction force in a block system and the acceleration of different objects under various conditions. It is concluded that the friction force on the top block is towards the right, and that on the bottom block is towards the left, leading to the top book falling off the left end of the bottom book.
  • #1
minimario
95
2

Homework Statement



UWQB18J.png

Homework Equations



F = ma

The Attempt at a Solution



When drawing a FBD for block 1, I couldn't figure out if the friction force between the blocks was toward the left or toward the right. Similar situation on block 2. How would I determine this?
 
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  • #2
Which direction do you expect for the acceleration of the top block?

Technically you can choose both directions for the force, but one choice will give a negative value for the force.
 
  • #3
Accelerate left. So the friction force would be left?
 
  • #4
Which way do the dishes accelerate in this video?
 
  • #5
To the right, but when I put a book on top of a heavier book and pull the heavier book right, the book goes left and falls off?
 
  • #6
minimario said:
To the right, but when I put a book on top of a heavier book and pull the heavier book right, the book goes left and falls off?
No, the top book goes right. It falls off the left end of the bottom book because the bottom book accelerates faster than the top book.
 
  • #7
Oh. So the friction on the top book would be right, and that on the bottom book would be left.
 
  • #8
minimario said:
Oh. So the friction on the top book would be right, and that on the bottom book would be left.
Yes, that's correct.
 

Related to Friction Forces Between Stacked Blocks: Determining Direction

1. What is the concept of "Block on Block with Friction" in physics?

In physics, "Block on Block with Friction" refers to a common problem that involves two blocks in contact with each other, where one block is resting on top of the other and there is friction between the two surfaces. This scenario is often used to study the effects of friction on the motion of objects.

2. How is friction involved in the "Block on Block with Friction" problem?

In the "Block on Block with Friction" problem, friction is a force that opposes the motion of the blocks. It arises due to the roughness of the surfaces in contact and can significantly affect the acceleration and velocity of the blocks.

3. What factors affect the magnitude of friction in the "Block on Block with Friction" problem?

The magnitude of friction in the "Block on Block with Friction" problem depends on several factors, including the normal force (the force exerted by one block on the other), the coefficient of friction (a material property that determines the friction between two surfaces), and the surface area in contact between the two blocks.

4. How is the motion of the blocks affected by the coefficient of friction?

The coefficient of friction plays a crucial role in determining the motion of the blocks in the "Block on Block with Friction" problem. A higher coefficient of friction will result in a greater force of friction, which will slow down the motion of the blocks. On the other hand, a lower coefficient of friction will result in less friction and allow the blocks to move more easily.

5. What real-life applications can be modeled using the "Block on Block with Friction" problem?

The "Block on Block with Friction" problem has many real-life applications, such as studying the motion of objects on an inclined plane or analyzing the forces involved in pushing or pulling an object. It can also be used to study the effects of friction in various mechanical systems, such as car brakes and conveyor belts.

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