Concept #1: Forces with Vertical Acceleration
Practice: The system shown below is pulled up with a constant 100 N. Calculate the tension between the blocks. Calculate the acceleration of the system (using +/- to indicate if it is up or down).
Practice: You are inside a bucket that is connected to a pulley above you by a vertical rope. You pull yourself up by pulling down on the other end of the rope. If the total mass of you plus bucket is 80 kg, how hard must you pull down on the rope to move up with a constant 2 m/s2 ?
Practice: A 70 kg diver steps off a board 9 m above the water and falls vertical to the water, from rest. If his downward motion is stopped 2.0 s after his body fist touches the water, what average upward force did the water exert on him?