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Unformatted text preview: Physics 120 Spring 2008 Problem Set 5 due Monday, April 7 cable f q
hinge 1. A concrete block of mass 200 kg hangs from the end of a uniform beam of mass 40.0 kg. A cable attached to the end of the beam keeps the system in equilibrium. (See figure above.) For the angles f = 20 and q = 30 , find (A) the tension in the cable, and (B) the horizontal and vertical components of the force on the beam from the hinge. 2. You have taken a summer job at a warehouse and have designed a method to help get heavy packages up a 15 ramp. In your system a package is attached to a rope which runs parallel to the ramp and over a pulley at the top of the ramp. crate After passing over the pulley the other end of the rope is attached to a counterweight which hangs straight down. (See diagram at right.) In your design the mass of the counterweight is always adjusted to be twice the mass of the package. 15 Your boss is worried about this pulley system. In particular, she is concerned that the package will be too difficult to handle at the top of the ramp and tells you to calculate its acceleration. To determine the influence of friction between the ramp and the package you run some tests. You find that you can push a 50 kg package with a horizontal force of 250 Newtons at a constant speed along a level floor made of the same material as the ramp. What acceleration value will you report to your boss? counter weight 3. A bicyclist (whose mass is 60 kg and whose bike has a mass of 12 kg) is coasting down a very long slope that makes a constant angle of 6 to the horizontal. It is observed that the bicyclist reaches a maximum speed of 40 mi/hr. If the bicyclist's cross section looks like a rectangle of width 40 cm and height 150 cm, determine the drag coefficient C for the bike and rider. (Assume that, at these speeds, air drag dominates over other kinds of friction.) ...
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