Static Friction Coefficient Problems

[jklops686]

Homework Statement

There are 2 questions in the attachments both with the same scenario I'm having troubles with.

Homework Equations

f=ma

The Attempt at a Solution

I tried finding the budging force between the 2 masses and that was about 4. I don't know where to go from there to find the acceleration.

 

[rude man]

Afraid I'm no help since I picked an answer for part 1 which does not correspond to any of the choices for answers in part 2.

Anyone else?

 

[jklops686]

Afraid I'm no help since I picked an answer for part 1 which does not correspond to any of the choices for answers in part 2.

Anyone else?

there is still one answer choice that isn't shown. couldn't get it in the screen shot

 

[ap123]

What was the last answer choice? (for both problems)

You've already worked out the maximum frictional force that can be on the 2kg object - 4N.
Since this is the only horizontal force on the object, then this is also the maximum net force on it.
So, just use F=ma to get the maximum acceleration.

( If this is not the hidden answer, then I will have to rethink it ).

 

[rude man]

What was the last answer choice? (for both problems)

You've already worked out the maximum frictional force that can be on the 2kg object - 4N.
Since this is the only horizontal force on the object, then this is also the maximum net force on it.
So, just use F=ma to get the maximum acceleration.

( If this is not the hidden answer, then I will have to rethink it ).

But 4N is not the F shown on the picture. (I agree it's the force on the 2 kg block.)

I picked one of the visible answers for part 1 but not for part 2 so my hope is for the remaining choice of part 2 to be my answer.

We need those last two answers jklops!

 

[haruspex]

But 4N is not the F shown on the picture.

ap123 wrote that his / her answer for the acceleration corresponded to a force of 4N on the top block.
jklops686, what do you get for F?