Two blocks, each with a mass $m$ = 0.178 kg, can slide without friction on a horizontal surface. initially, block 1 is in motion with a speed $v$ = 1.20 m/s; block 2 is at rest. when block 1 collides with block 2, a spring bumper on block 1 is compressed. maximum compression of the spring occurs when the two blocks move with the same speed, $v$/2 = 0.600 m/s. if the maximum compression of the spring is 1.80 cm, what is its force constant?