A scanning electron microscope (SEM) accelerates electrons to very high speeds and fires those electrons at a sample. By looking at the way that the electrons interact with the sample, we can generate detailed images of objects we can't get with a traditional optical microscope, like mineral crystals or biological cells. To accomplish this goal, an SEM uses an accelerating voltage around 10kV (high voltage generally means better resolution). One such SEM uses an accelerating voltage of 13kV. How fast are the electrons moving after they pass through this accelerating voltage?

Aball is thrown from the top of a building with an initial velocity of 21.9 m/s straight upward, at an initial height of 51.6 m above the ground. the ball just misses the edge of the roof on its way down, as shown in the figure. (a) determine the time needed for the ball to reach its maximum height. (b) determine the maximum height. (c) determine the time needed for the ball to return to the height from which it was thrown, and the velocity of the ball at that instant. (d) determine the time needed for the ball to reach the ground. (e) determine the velocity and position of the ball at t = 5.35 s.