9. A block , 0.7 kg , is released from rest a height above a vertical spring that has a spring constant of 400N/m. The block compresses the spring 19cm and stops temporarily. How much work is done: a) by the block on the spring? b) by the spring on the block? c) What is the original value of the height before it is dropped? d) If the block is release at twice the height as part c, what would the maximum compression of the spring be