SPRING AND FRICTION

A MASSLESS SPRING WITH FORCE CONSTANT K = 400 NEWTONS PER METER IS FASTENED AT ITS LEFT END TO A VERTICAL WALL, AS SHOWN IN FIGURE I. INITIALLY, BLOCK C (MASS MC = 4.0 KG) AND BLOCK D (MASS MD = 2.0 KG) REST ON A HORIZONTAL SURFACE WITH BLOCK C IN CONTACT WITH THE SPRING (BUT NOT COMPRESSING IT) AND WITH BLOCK D IN CONTACT WITH BLOCK C. BLOCK C IS THEN MOVED TO THE LEFT, COMPRESSING THE SPRING A DISTANCE OF 0.50 M, AND HELD IN PLACE WHILE BLOCK D REMAINS AT RESTS AS SHOWN IN FIGURE II (USE g = 10 m/s2)

A) DETERMINE THE ELASTIC ENERGY STORED IN THE COMPRESSED SPRING.

BLOCK C IS THEN RELEASED AND ACCELERATES TO THE RIGHT, TOWARD BLOCK D. THE SURFACE IS ROUGH AND THE COEFFICIENT OF FRICTION BETWEEN EACH BLOCK AND THE SURFACE IS 0.4. THE TWO BLOCKS COLLIDE INSTANTANEOUSLY, STICK TOGETHER, AND MOVE TOT HE RIGHT. REMEMBER THAT THE SPRING IS NOT ATTACHED TO BLOCK C. DETERMINE EACH OF THE FOLLOWING:

B) THE SPEED VC OF BLOCK C JUST BEFORE IT COLLIDES WITH BLOCK D.

C) THE SPEED VF OF BLOCKS C AND D JUST AFTER THEY COLLIDE.

D) THE HORIZONTAL DISTANCE THE BLOCKS MOVE BEFORE COMING TO REST.