Tension between 2 blocks and friction.

AI Thread Summary
A block system consisting of two masses (m1 = 2 kg and m2 = 3 kg) is pulled by a force of 25 N, with a friction coefficient of 0.14. The calculated acceleration of the system is approximately 3.6 m/s². The total frictional force acting on the blocks is 6.867 N, with individual frictional forces of approximately 2.7468 N for m1 and 4.1202 N for m2. The tension in the string between the blocks was ultimately found to be 10 N after resolving the forces. The discussion highlights the importance of free body diagrams and accurate force summation in solving for tension in such systems.
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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