A glider with mass m = 0.8 kg sits on a frictionless air track. It is connected to a massless spring with force constant k = 30 N/m. The glider is initially at x=0, and the spring is relaxed. You then hit the glider with a hammer, which gives it an initial velocity of υ0 = 8 m/s in the positive x direction. At what x positions will the speed of the glider be zero?