Please don't report. It's not a homework question. Yesterday on my physics test there was this question. there is a block of mass $m$ connected to a spring as shown in the figure. the spring constant is $k$ and the friction coefficient between the block and the floor is $\mu$. they have asked what is the minimum horizontal force $F$ applied as shown in the figure so that the block starts to move. I answered $\mu mg$ considering the whole spring mass system as a single system of mass $m$. but a friend said afterwards that it would be $\frac12 \mu mg$ because the force is being applied on the spring and if the force elongates it by $x$ length, $$kx=\mu mg$$ and, $$Fx=\frac12kx^2$$ so solving, $$F=\frac12µmg$$ . Is he right ? please explain in detail why he is right or wrong. And please point out the problem in my thinking if I am wrong.
what he is saying is that he is equating the increase in potential energy to the work done by the force on the spring. I don't understand his point.