- #1
jb007
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Homework Statement
I am stuck on this problem:
So the question is asking for F21, F12, F32, and F23. (That's the force by 2 on 1).
The mass of m2 is variable.
There are four cases where I need to solve for the forces: when m2 has mass of 3kg, 0.3kg, 0.03kg, and 0kg.
The mass of m1 = 2.5kg, the mass of 3 = 3.5kg.
Also assume that friction is neglected.
I am confused on how to resolved the tension force in a system with numerous objects.
The T is constant, 3N. imagine there's a person pulling on the string with a constant force of 3N.
I know the acceleration of all three carts in each case should be the same.
But how do I solve for the tension force in the strings between the carts?
Homework Equations
F=ma
Newton's 3rd Law
Pretty sure that's all I really need here.
The Attempt at a Solution
[/B]Ok, so I drew free-body-diagrams for each case. I know T is always equal to 3N. The weight force and normal force of all three carts aren't taken into account.
Should the tension force in the strings be constant?
Suppose I were to do case 1 with m2 = 3kg:
T=3N
Fnet = 3N
3 = (m1+m2+m3)a
a = 3/(2.5+3+3.5) = 0.33 m/s/s (for the whole system, so each cart has the same acceleration)
Going from left to right, solving for F23, would the force m2 on m3 be equal to (m2+m1)0.33?
Then would F32 be equal in magnitude but in the opposite direction of F23 because of Newton's 3rd Law?
I'm not sure what to include or exclude when I'm calculating a force within a specific part of a system.
Any pointers would be very helpful. Thanks.