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Unformatted text preview: homework 10 – GADHIA, TEJAS – Due: Apr 4 2007, 4:00 am 1 Question 1 part 1 of 1 10 points A uniform rod of mass 4 . 4 kg is 17 m long. The rod is pivoted about a horizontal, fric- tionless pin at the end of a thin extension (of negligible mass) a distance 17 m from the cen- ter of mass of the rod. Initially the rod makes an angle of 64 ◦ with the horizontal. The rod is released from rest at an angle of 64 ◦ with the horizontal, as shown in the figure below The acceleration of gravity is 9 . 8 m / s 2 . Hint: The moment of inertia of the rod about its center-of-mass is I cm = 1 12 mℓ 2 . 17 m 17 m 4 . 4 kg O 64 ◦ What is the magnitude of the horizontal acceleration of the center of mass of the rod at the instant the rod is in a horizontal position? Answer in units of rad / s 2 . Question 2 part 1 of 3 10 points A 5 . 5 kg mass is connected by a light cord to a 3 . 3 kg mass on a smooth surface as shown. The pulley rotates about a frictionless axle and has a moment of inertia of 0 . 19 kg · m 2 and a radius of 0 . 85 m. The acceleration of gravity is 9 . 81m / s 2 . b 5 . 5kg 3 . 3kg F 1 F 2 R Note: Figure is not drawn to scale Assume that the cord does not slip on the pulley. a) What is the acceleration of the two masses? Answer in units of m / s 2 . Question 3 part 2 of 3 10 points b) What is the magnitude of the force F 1 ? Answer in units of N. Question 4 part 3 of 3 10 points c) What is the magnitude of the force F 2 ? Answer in units of N. Question 5 part 1 of 2 10 points Assume: When the disk lands on the sur- face it does not bounce. The disk has mass 8 kg and outer radius 70 cm with a radial mass distribution (which may not be uniform) so that its moment of inertia is 3 7 mR 2 . The disk is rotating at angular speed 4 rad / s around its axis when it touches the surface, as shown in the figure below. The disk is carefully lowered onto a horizontal sur- face and released at time t with zero initial linear velocity along the surface. The coef- ficient of friction between the disk and the surface is 0 . 02 ....
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This note was uploaded on 04/05/2010 for the course BIO 52435 taught by Professor Clerck during the Spring '10 term at University of Texas.
- Spring '10