5. (8 pt) In the figure below the coefficient of static friction between mass ma and the FT1 FTZ table is 0.40, whereas the coefficient of kinetic friction is 0.20. (a) What 35 45- minimum value of mA will keep the system from starting to move? (b) What m = 3 kg value(s) of ma will keep the system moving at constant speed? Ignore masses of the cord and the (frictionless) pulley. You need to draw a FBD for each box. 2. (4 pt) An object hangs between two walls which are 1.8 m apart. If the rope sags 15 below horizontal and the object's mass is 1.5 kg, what is the tension in the rope? Be sure to draw a FBD MA of the shoe. MB 2.0 kg 6. (5 pt) You want to park on a very steep street in San Francisco, which has an angle of about 30 degrees. The coefficient of static friction between hard rubber and normal street pavement is about 0.90. On how steep a hill (maximum angle) can you leave a 3. (8p) On the diagram below the incline has a slope of 0 = 30. car parked? Can you safely park on the steep street? Draw a FBD of the car. (a) If the kinetic friction of the block on the incline is ux = 0.30 and the block slides 7. (5 pt) The diagram represents two skydivers, an instructor (70 kg) and a student (60 kg), for 0.45 m to the bottom of the incline, what is the speed of the block at the bottom of connected by a harness. While descending they measure their acceleration to be the incline? 2 m/s2 while they experience air drag, Farag (it is mostly due to the aerodynamic (b) If the kinetic friction of the block on the flat ground is uk = 0.25 how far does the profile of the student, who takes the "front seat"). Calculate this Farag force. block slide (measured from the bottom of the incline) before it comes to a full stop? mA = 70 kg HK = 0.3 MB = 60 kg a = 2.0 m/s2 HK = 0.2 Farag 4. (5 pt). An old miser with a bag of gold jumps onto the surface of a frozen lake and hopes to coast to civilization on the other side. Unfortunately the ice does have a coefficient of kinetic friction #x = 0.08. He slides for 80 m and then stops. (Now he has to walk.) How fast was he moving at the start of his coast