A spring with a k value of 200 N/m is compressed by 20 cm. It has a 10 kg mass attached to it. A. What is the Potential energy of this spring? B. What is the Kinetic energy of the mass C. What is the velocity of the box when the spring is released

Emmy kicks a soccer ball up at an angle of 45° over a level field. she watches the ball's trajectory and notices that it lands, two seconds after being kicked, about 20 m away to the north. assume that air resistance is negligible, and plot the horizontal and vertical components of the ball's velocity as a function of time. consider only the time that the ball is in the air, after being kicked but before landing. take "north" and "up" as the positive ‑ and ‑directions, respectively, and use ≈10 m/s2 for the downward acceleration due to gravity.