# Mechanics problem.

1. The problem statement, all variables and given/known data

Find the minimum Force required to move M2.
M1=3kg.M2=5kg,$\mu$1=0.4and$\mu$2=0.6.
2. Relevant equations

Net f =Ma

3. The attempt at a solution
For a displacement ‘x’ force applied on the block M1 by the spring=kx.
From free body diagrams we can get
F=$\mu$1*M1*g+kx.
When spring applies kx on block 1 it will apply kx to block 2 but in opposite direction.The block 2 will move when kx=$\mu$2*m2*g.Combining Two equations we get f= 41.16.
It is not right,somebody told me that I could not do this question in this way because force exerted by the spring is not constant.But maximum force that spring can exert on block is $\mu$2*m2*g and if F exceeds than that then block 2 should start moving.This thing does not have anything to do with the nature of force.

http://ift.tt/UePciU