Arubber ball is dropped and bounces vertically from a horizontal concrete floor. if the ball has a speed of 3 m/s just before striking the floor, and a speed of 6.5 m/s just after bouncing, find the average force of the floor on the ball. assume that the ball is in contact with the floor for 0.32 s, and that the mass of the ball is 0.42 kg

Which accurately compares concave and convex lenses?

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.

What causes the development of most clouds and precipitation in the atmosphere?