¿Cuál es la frecuencia de rotación en la tierra?

Quantum mechanics applies to subatomic, atomic, nanometer-size, and micrometer-size systems. nanometer, micrometer, and kilometer-size systems. atomic, nanometer-size, and micrometer-size systems. subatomic, atomic, and nanometer-size systems.

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.

Ben (55kg) is standing on very slippery ice when junior (25kg) bumps into him. junior was moving at a speed of 8 m/s before the collision and ben and junior embrace after the collision. find the speed of ben and junior as they move across the ice after the collision. give the answer in m/s. describe the work you did to get the answer.