A vertical spring with a spring constant of 470 N/m is mounted on the floor. From directly above the spring, which is unstrained, a 0.30 kg block is dropped from rest. It collides with and sticks to the spring, which is compressed by 2.5 cm in bringing the block to a momentary halt. Assuming air resistance is negligible, from what height (in cm) above the compressed spring was the block dropped? ... I tried using KEo + PEo + SPEo = KEf + PEf + SPEf ... but, I can't get anywhere ... ... I found out that the frequency is 18.05hz and it's relative time is .056 seconds - and that's where I'm stuck! HELP!