3. [-I5.9 Points] DETAILS SERCP11 5.5.P.021. MY NOTES ASK YOUR TEACH ER A block of mass 4.00 kg is placed against a horizontal spring of constant k = 835 N/m and pushed so the spring compresses by 0.0600 m. HINT (a) What is the elastic potential energy of the block-spring system (in J)? |:lJ (b) If the block is now released and the surface is frictionless, calculate the block's speed (in m/s) after leaving the spring. m/s 4. [-I5.9 Points] DETAILS SERCP11 5.6.P.033. MY NOTES ASK YOUR TEACH ER A child and sled with a combined mass of 55.0 kg slide down a frictionless slope. If the sled starts from rest and has a speed of 2.50 m/s at the bottom, what is the height of the hill? |:|m