1. The problem statement, all variables and given/known data A block of unknown material weighs 50 N in air and 20 N in water. What is the buoyant force of water? 2. Relevant equations I know how to calculate density etc. I thought the formula to use was -density x V x g but it's not correct. 1. The problem statement, all variables and given/known data A x Kg mass is attached to a horizontal spring of constant 20 N/m and set into harmonic motion with an amplitude = 0.2m. What is the total mechanical ernergy of the system? I have no idea what to do... Some help would be greatly appreciated. Thanks!