Tension between 2 blocks and friction.

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Homework Help Overview

The discussion revolves around a problem involving two blocks connected by a string, being pulled across a surface with friction. The participants are tasked with finding the tension in the string given the masses of the blocks, the applied force, and the coefficient of friction.

Discussion Character

  • Mixed

Approaches and Questions Raised

  • Participants discuss the calculation of frictional forces and the application of Newton's laws. There are attempts to clarify the pulling forces on each block and the overall acceleration. Questions arise about the accuracy of the frictional force values and the method of summing forces.

Discussion Status

The conversation reflects a mix of attempts to clarify calculations and methods, with some participants expressing uncertainty about their reasoning. While one participant claims to have resolved the problem, others are still exploring their understanding of the forces involved.

Contextual Notes

There are indications of confusion regarding the correct values for frictional forces and the acceleration of the blocks. Participants are also grappling with the implications of their calculations and the necessity of drawing free body diagrams.

CaptainSFS
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Homework Statement



hm4.gif


A block of mass m1 = 2 kg and a block of mass m2 = 3 kg are tied together and are pulled from rest across the floor by a force of P = 25 N. The coefficient of friction of the blocks with the floor is µ = 0.14.

I found the acceleration to be 3.6266 m/s2.

I need to find the tension in the string between the blocks.

Homework Equations



F=ma and Ff=u(mg)

The Attempt at a Solution



The total frictional force is 6.867 N. m1 has a frictional force of 2.7468 i think, and m2 has a frictional force of 6.7596 i think. I think the pulling force on m1 is 7.2532 N. I mean, i tried creating different summations of the forces, but I don't know what I'm doing wrong. I'm sure I could figure it out, but I need to at least know how to add the forces up in each direction. Thanks so much.
 
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CaptainSFS said:

Homework Statement



hm4.gif


A block of mass m1 = 2 kg and a block of mass m2 = 3 kg are tied together and are pulled from rest across the floor by a force of P = 25 N. The coefficient of friction of the blocks with the floor is µ = 0.14.

I found the acceleration to be 3.6266 m/s2.
Good. You should round it off though to 3.6

The total frictional force is 6.867 N.
yes
m1 has a frictional force of 2.7468 i think,
yes
and m2 has a frictional force of 6.7596 i think.
where did you get this?
I think the pulling force on m1 is 7.2532 N.
how did you arrive at this?
I mean, i tried creating different summations of the forces, but I don't know what I'm doing wrong.
Draw a Free Body Diagram of block 1 (isolate it) , and examine the forces acting on it to solve for T using Newton 2. What is the acceleration of block 1?
 
okay, I typed the wrong number in for m2's frictional force. I meant to type in 4.1202 N. I arrived at m1's pulling force by (2)(3.6) = F. Right, I thought I tried creating a FBD but for some reason I'm doing something wrong. Is the acceleration on block m1 = 2.25 m/s2? At this point I am not sure what I am supposed to do.

EDIT: wait, doesn't the acceleration have to be equal to 3.6m/s2?
 
Last edited:
Hey, if someone could help me. I'm really stuck on this one, I just think I've dug myself a deeper hole trying to work this out. I would really appreciate any more help.

EDIT: I solved it. it's 10 N...
 
Last edited:

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