(11%) Problem 5: A book is resting on a horizontal tabletop. The book is stationary and there are no extemal forces applied to the book. If necessary, use Fs for the force of static friction and Fk as the force of kinetic friction.

F 0 EC FAC $ Ed and Al are pushing on a couch as shown in the picture and it doesn't slip. Ed is pushing with a force of 198.9 N at an angle of 0 = 54 degrees with respect to the vertical and Al is pushing with a force of 60.2 N at an angle of = 35.4 degrees with respect to the horizontal. If the couch has a mass of 83 kg and the coefficients of static and kinetic friction between the couch and the floor are μg = 0.53, and k = 0.39, what is the magnitude of the force of friction exerted by the floor on the couch? Click here for a hint F

9. A 75 N crate is at rest on an incline that is inclined a 25° above the horizontal. The coefficient of static friction between the crate and the incline is 0.25 and the coefficient of kinetic friction between the crate and the incline is 0.15. (a) What is the minimum magnitude of a force parallel to the incline that will prevent the crate from sliding down the incline? (b) What is the minimum magnitude of the force parallel to the incline that will start the crate to move up the incline? (c) Include a force (or free body) diagram of each situation.

A setup similar to the one shown in the figure below is often used in hospitals to support and apply a horizontal traction force to an injured leg. (Let m = 5.25 kg and 8 = 75.0°.) (a) Determine the force of tension in the rope supporting the leg. N (b) What is the traction force exerted to the right on the leg? Additional Materials еВook

a bird feeder that weighs 199.3 N. The feeder is supported by a vertical wire, which is in turn tied to two wires, each of which is attached to a horizontal support. The left wire makes a 60° angle with the support, while the right wire makes a 30° angle. What is the tension in each wire (in N)? (A) left wire, (B) right wire, (C)bottom wire

A 26.8 kg box sits on a ramp at an angle of 13° above the horizontal. If the coefficient of static friction between the box on the ramp is 0.215, what minimum applied force is required to keep the box at rest?

In about 1915, Henry Sincosky of Philadelphia suspended himself from a rafter by gripping the rafter with the thumb of each hand on one side and the fingers on the other side (see the figure). Sincosky's mass was 83.0 kg. If the coefficient of static friction between hand and rafter was 0.710, what was the least magnitude of the normal force on the rafter from each thumb or opposite fingers? (After suspending himself, Sincosky chinned himself on the rafter and then moved hand-over-hand along the rafter. If you do not think Sincosky's grip was remarkable, try to repeat his stunt.) Number Units

The figure below shows a block weighing 22 N in contact with a vertical wall. Two forces are applied to the block, in addition to gravity, a horizontal force F of magnitude 60 N which pushes the block against a vertical wall and a force P of magnitude 62 N which pushes upward on the bottom of the block parallel to the wall. The coefficient of static friction between the wall and the block is 0.55 and the coefficient of kinetic friction between them is 0.38. Is the frictional force acting on the block static or kinetic, what is its magnitude and in what direction does it point? F P