A system consisting
of two movable blocks and an unstretched spring with a spring constant
of 98.1 N/m are connected as shown. At the instant shown, the spring's
length is 20 m more than its unstretched length. The coefficient of friction
between the two blocks is 0.6 and that between the floor and the lower
block is 0.1 . The mass of the blocks A and B are 10 Kg and
20 Kg respectively. Find the accelerations of block A and block B
when the spring's length is 10 m more than its unstretched length a ) 3.92 m / s ^{2}
, 1.47 m / s ^{2} 


Let N_{A} and N_{B} be the normal reactions on blocks A and B respectively; M_{A} and M_{B} the mass of the blocks ; m_{1} and m_{2} be the coefficients of friction between the blocks and, the block B and the floor respectively ; k , the spring constant (stiffness constant) and x be the elongation of the spring. Since there is no
vertical motion , The equation of motion
of the block A when x =10 meters is , The equation of motion
of the block B when x =10 meters is , Hence the accelerations
of the blocks A and B are 