Forces acting on a block that is pushed against a wall

AI Thread Summary
To move a block pushed against a wall, the applied force must exceed the frictional force. The calculations show that for upward motion, the force must be greater than 44N, while for downward motion, it must be less than 20N. The discussion concludes that the correct option is likely D based on these conditions. Participants agree that the calculations presented are accurate. Understanding the balance of forces is crucial for determining the block's movement.
MatinSAR
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Homework Statement
What should be the magnitude of force F so that the object is definitely moving?(Frictional force is equal to 0.5 for each newton of vertical force on the surface.)
A)25 B)30 C)40 D)50
Relevant Equations
##F_{net} =ma##
##f_{s} =µ_sN##
##f_{k} =µ_kN##
Picture of problem:
1677619868908.png


For the object to be moving, it must overcome friction.

##f=0.5*0.6F = 0.3F##
##mg=22N##

Upward motion:
##0.8F>mg+f \rightarrow 0.5F>22 \rightarrow F>44N ##

Downward motion:
##0.8F+f<mg \rightarrow 1.1F<22 \rightarrow F<20N ##

I think correct option is D. Can you please guide me if I'm wrong?
 
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Your work looks good to me.
 
TSny said:
Your work looks good to me.
Thank you for your help.
 
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