(adsbygoogle = window.adsbygoogle || []).push({}); Physics HW help!? Normal Force between two objects?

Hi, Ive had trouble trying to gigure out this problem! I would really appreciate the help!

The Problem:

Three blocks rest on a frictionless, horizontal table (see figure below), with m1 = 7 kg and m3 = 12 kg. A horizontal force F = 103 N is applied to block 1, and the acceleration of all three blocks is found to be 3.4 m/s2.

A. Find m2

B. What is the normal force between blocks 2 and 3?

I coouldnt post the figure(picture) but I can explain it.. The three blocks are all lined up against each other. So block 1(m1) is first, then block two(m2) is right next to block1, then block 3(m3) is against block 2.. they are all lined up on top of the table.. side by side..

Relevant equation:

I found the mass of block 2 by doing F=ma. or M= F/A

7+12+m2= 103/3.4

19+m2= 30.29

m2= 11.29

So M2 is 11.29

My only problem is that I don't know how to find the normal force between blocks 2 and 3

Attempt at a Solution:

The way i tried to find the solution was figuring out what force is acting on block three so that it can accelerate 3.4 m/s^2.

I did:

F=m*a

F=12*3.4

F= 40.8

Now, is 40.8 the normal force between block two and three or is that just an irrelevant number?

Thank you so much for the help!

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

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# Homework Help: Physics HW help? Normal Force between two objects?

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