Two rams run toward each other. One ram has a mass of 49 kg and runs west with a speed of 7 m/s, while the other has a mass of 52 kg and runs east with
a speed of 9 m/s. What will the momentum of the system made up of the two
rams be after they collide? Assume the total momentum of the system is
conserved
A. 811 kg-m/s west
B. 811 kg-m/s east
C. 125 kg-m/s west
O D. 125 kg-m/s east
S

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.