3. A 3 kg block is fastened to a vertical spring that has a spring constant of 800 Nlm. A 1.2 kg block rests on top of the 3 kg block, as shown below. (a) When the blocks are at rest, how much is the spring compressed from its uncompressed length? (b) The blocks are now pushed down so that they oscillate. Determine the frequency of the oscillation. (c) Determine the maximum magnitude of the acceleration that the blocks can attain and still remain in contact at all times. k 800 N/m