A 70 kg student is riding on a skateboard at 4m/s. A 60 kg student is also riding a skateboard at 4 m/s. Which statement below demonstrates an understanding of
Newton's 1st Law of Motion?
A. Since both students are traveling at the same speed they must have the same
inertia
B. Since both students are traveling at the same speed they must have the same
mass
C. One student has more mass and therefore more inertia

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.