Acrate attached to a spring is being pulled across a flat frictionless surface. the spring is stretched 0.82 m, the crate is accelerating at 0.93 m/s squared and the mass of the crate is 40 kg. what is the spring constant?

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.