28. someone throws a rubber ball vertically upward from the roof of a building 8.00 m in height. the ball rises,

then falls. it just misses the edge of the roof, and strikes the ground. if the ball is in the air for 3.00 s, what

was its initial velocity? (disregard air resistance.)

Determine the time it takes for a satellite to orbit the earth in a circular "near-earth" orbit. the definition of "near-earth" orbit is one which is at a height above the surface of the earth which is small compared to the radius of the earth, so that you may take the acceleration due to gravity as essentially the same as that on the surface. does your result depend on the mass of the satellite?