Force Analysis of 3 Blocks on Horizontal Surface

AI Thread Summary
The discussion focuses on analyzing the forces acting on three blocks placed on a frictionless horizontal surface when a force of 8N is applied. The user is uncertain about the reaction forces between the blocks and seeks clarification on how to represent these forces correctly in a Free Body Diagram (FBD). It is emphasized that only the forces acting on each block should be included in the FBD, excluding forces exerted by the blocks themselves. For instance, in Block 3, only the gravitational force, normal reaction, and the force from Block 2 should be represented. The advice provided aims to help accurately depict the interactions and forces involved in the system.
brad sue
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Hi ,

please help me with this question

We have 3 blocks on an horizontal surface (frictionless). We apply a force F=8N
What are the forces on each 3 blocks.

My solution:

For the block 1 I found: m1g(down), Normal reaction R1 ( up), R2/1 (left)
Here is there an R1/2 (right) force of block 1 on the force F=8N?

Block 2: m2g( down), normal reaction R2(up), R3/2, R1/2

Block3: m3g (down), normal reaction R3(up), R2/3,R3/2

My problem is about the reaction between blocks
I am not sure about that. Can someone help me Please

Thank you
 
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Whenever, you are solving problems of this type, the first thing you should do is draw a Free Body Force Diagram. In this case, draw each of the blocks and the forces acting on the blocks.

When you are drawing the Free Body diagram, take care to mark only the forces which are acting ON the body (in this case block) and not due to the body.

For example, in Block 3, the forces acting on the block will be mg, normal reaction(R3) and R2/3 only. The force which the 3rd block exerts on the second block(R3/2) should not be drawn in the Free Body diagram of Block 3
 
Last edited:
siddharth said:
Whenever, you are solving problems of this type, the first thing you should do is draw a Free Body Force Diagram. In this case, draw each of the blocks and the forces acting on the blocks.

When you are drawing the Free Body diagram, take care to mark only the forces which are acting ON the body (in this case block) and not due to the body.

For example, in Block 3, the forces acting on the block will be mg, normal reaction(R3) and R2/3 only. The force which the 3rd block exerts on the second block(R3/2) should not be drawn in the Free Body diagram of Block 3

Thanks a lot I am going to do to it!
 
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