What is the ranking of forces in a problem on ranking forces?

[isukatphysics69]

Homework Statement

Homework Equations

f=ma

The Attempt at a Solution

( i have put numerous different forces into the answer box and nothing worked. i was just taking a screenshot of problem here)
Edit: never mind about kinetic friction with wall i just saw that there is no friction with wall.
[/B]
netforceavertical = Fpah - mg - fstatic = 0
netforcebvertical = Fpba - mg - fstatic = 0
acceleration is equal to 0 for both boxes and velocity upwards so the pushing force is greater than mg, mg for box A is greater than mg for box B , not sure where the frictional forces between boxes would rank here but i know they would be equal from Newtons third law since both boxes are accelerating upwards at constant speed. the static frictional force between the two boxes are equivalent. There will also be a kinetic frictional force between the box B and the wall which would be negative so i think that would rank after the static frictional forces between the boxes. not sure if i am doing this correct

 

[isukatphysics69]

Force between hand and A and A and B is equal since both moving up at constant velocity, this beats gravity forces and since A has more mass than B the FGAE>FGBE and these gravitational forces id imagine are greater than the equivalent static frictional forces between the two boxes?

 

[haruspex]

Force between hand and A and A and B is equal since both moving up at constant velocity

I see no logic to that.
Consider the two blocks separately. List the vertical forces on each, and write out the "relevant equation" in each case.

 

[isukatphysics69]

I see no logic to that.
Consider the two blocks separately. List the vertical forces on each, and write out the "relevant equation" in each case.

I think that's what the velocity arrow between the two are supposed to represent but i will do it

 

[isukatphysics69]

Force pushing on A greater than force gravity on A, There is no pushing force on B so i omit that. gravity on a > gravity on b and static frictional forces are equal Newtons third law pair. There is no pushing force on b but a normal force as a result from block A pushing on it which is a horizontal force not vertical

 

[haruspex]

I think that's what the velocity arrow between the two are supposed to represent but i will do it

Yes, they are both moving at the same constant velocity, but that does not mean FHAH=FHBA.

 

[isukatphysics69]

Yes, they are both moving at the same constant velocity, but that does not mean FHAH=FHBA.

i post something above ^
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[haruspex]

View attachment 223213
Force pushing on A greater than force gravity on A, There is no pushing force on B so i omit that. gravity on a > gravity on b and static frictional forces are equal Newtons third law pair. There is no pushing force on b but a normal force as a result from block A pushing on it which is a horizontal force not vertical

I encourage you to stop thinking about the ranking for now and concentrate on getting the right force balance equations.

 

[haruspex]

Thread abandoned by OP and recreated at https://www.physicsforums.com/threads/ranking-forces.943948/.