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Unformatted text preview: HWCH6
9th Edition CH6 Problems: 51, 57, 67, 78 8th Edition CH6 Problems: 53, 55, 69, 70
51. An airplane is ying in a horizontal circle at a speed of 480 km/h (Fig.642). If its wings are tilted at angle = 40o to the horizontal, what is the radius of the circle in which the plane is ying? Assume that the required force is provided entirely by an "aerodynamic lift" that is perpendicular to the wing surface. 57. A puck of mass m = 1:50 kg slides in a circle of radius r = 20:0 cm on a frictionless table while attached to a hanging cylinder of mass M = 2:50 kg by a cord through a hole in the table (Fig. 644). What speed keeps the cylinder at rest? 67 In Fig. 653, a crate slides down an inclined rightangled trough. The coe cient of kinetic friction between the crate and the trough is k . What is the acceleration of the crate in terms of k ; ; and g? 78. A student wants to determine the coe cients of static friction and kinetic friction between a box and a plank. She places the box on the plank and gradually raises one end of the plank. When the angle of inclination with the horizontal reaches 30o , the box starts to slip. and it then slides 2.5 m down the plank in 4.0 s at constant acceleration. What are (a) the coe cient of static friction and (b) the coe cient of kinetic friction between the box and the plank? 1 ...
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This note was uploaded on 05/14/2011 for the course ECON 101 taught by Professor Asdaf during the Spring '11 term at Universidad de San Buenaventura Bogota.
 Spring '11
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