5. A 4kg block on a frictionless table is attached to a horizontal spring with k=400N/m. The spring is initially compressed 5cm. Find (a) the work is done on the block by the spring as the block moves from x1= -5cm to its equilibrium position x2=0cm and (b) the speed of the block at x2.

Will you chech and finish these for me, because i am stumped with them.

The experiment was repeated many years later but the gases were mixed in a different type of container. a white solid was obtained which was xenon fluoride. predict whether you think 1) krypton and 2) radon will react with fluorine. explain reasons for your predictions

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.