Julie drives 100 mi to grandmother's house. on the way to grandmother's, julie drives half the distance at 33.0 and half the distance at 80.0 . on her return trip, she drives half the time at 33.0 and half the time at 80.0 . what is julie's average speed on the way to grandmother's house? what is her average speed on the return trip?

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.