Solve Free Body Diagram: 2 Boxes, m1=35kg, m2=45kg

AI Thread Summary
The discussion focuses on solving a physics problem involving two boxes of different masses, m1=35kg and m2=45kg, suspended from a rope over a rod. Participants express confusion about interpreting the problem and drawing the free body diagram (FBD). They suggest treating the setup as a frictionless pulley system and emphasize the need to apply Newton's second law to each mass separately. A consistent sign convention is recommended to clarify the relationship between the accelerations of the two masses. The conversation highlights the importance of correctly visualizing the forces at play to solve for acceleration, tension, and displacement.
cindy!
Messages
4
Reaction score
0

Homework Statement



Two boxes of masses m=35kg and m2=45kg, are hung vertically from opposite ends of a rope passing over a rigid horizontal metal rod. They system starts moving from rest. Assuming that friction between the rod and the rope is negligible, determine the magnitude of
(a) the acceleration of the boxes
(b) the tension in the rope
(c) the magnitude of each box's displacement after 0.5s

Homework Equations



Fnet=ma
Fnet= FT - Fg
ma=FT-Fg

(well i think this is right, depending on how the free body diagram is drawn..)


The Attempt at a Solution



Well...I have no idea what the question is saying, I am unsure how to draw the actual diagram and also how to draw the FBD. This is how i inteperted it:

2dtzqs5.jpg


4bso6zq.jpg
 
Physics news on Phys.org
maybe I am reading it wrong, but the way i read it was that there are 2 boxes tied to each other with a rope and that rope is hung on an iron bar.
 
What's F_R in your diagram?? I agree with fizz on the interpretation of the problem.
 
I assume you are to treat this just as you would if the rod were a frictionless (and massless) pulley. Draw a free body diagram for each mass separately.

Apply Newton's 2nd law to each mass (just like in your equations) to get two equations, which you'll solve together. Hint: Adopt a consistent sign convention, for example: up is positive and down is negative. Let "a" be the magnitude of the acceleration; how do the accelerations of the masses relate to each other?
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
Thread 'Voltmeter readings for this circuit with switches'
TL;DR Summary: I would like to know the voltmeter readings on the two resistors separately in the picture in the following cases , When one of the keys is closed When both of them are opened (Knowing that the battery has negligible internal resistance) My thoughts for the first case , one of them must be 12 volt while the other is 0 The second case we'll I think both voltmeter readings should be 12 volt since they are both parallel to the battery and they involve the key within what the...
Thread 'Trying to understand the logic behind adding vectors with an angle between them'
My initial calculation was to subtract V1 from V2 to show that from the perspective of the second aircraft the first one is -300km/h. So i checked with ChatGPT and it said I cant just subtract them because I have an angle between them. So I dont understand the reasoning of it. Like why should a velocity be dependent on an angle? I was thinking about how it would look like if the planes where parallel to each other, and then how it look like if one is turning away and I dont see it. Since...
Back
Top