PHYS 1111 Intro Physics I Mechanics Nguyen Spring 2015 Homework 09 Daniel Hernandez Due date Sat Apr 4 11 59 59 pm 2015 EDT An appliance box has a square base with sides of length L and has rectangular sides with a height of L The top of the box is missing The box is made from cardboard of uniform thickness and density What is the height of the center of mass of this open box with respect to the bottom of the box A B C D E L 10 2L 5 4L 5 L 2 L 5 You are correct Your receipt no is 156 3047 Three identical uniform meter sticks are placed on the floor The first stick lies along the y axis from y 0 580 m to y 1 58 m The second stick lies along the x axis from x 0 370 m to x 1 37 m The third stick is positioned so that one end is on the x axis at x 0 520 m and the other end is on the y axis at y 0 854 m Calculate the location of the center of mass of the meter sticks Enter the x position first then the y position 0 3770 m 0 5020 m You are correct Your receipt no is 156 2213 The drill used by most dentists today is powered by a small air turbine that can operate at angular speeds of 304000 rpm These drills along with ultrasonic dental drills are the fastest turbines in the world far exceeding the angular speeds of jet engines Suppose a drill starts at rest and comes up to operating speed in 2 04 s Calculate the angular acceleration produced by the drill assuming it to be constant Give answer in rev s2 Do not enter unit 2480 You are correct Your receipt no is 156 9550 How many revolutions does the drill bit make as it comes up to speed Do not enter unit 5170 You are correct Your receipt no is 156 1566 A centrifuge is a common laboratory instrument that separates components of differing densities in solution This is accomplished by spinning a sample around in a circle with a large angular speed Suppose that after a centrifuge in a medical laboratory is turned off it continues to rotate with a constant angular deceleration for 11 7 s before coming to rest If its initial angular speed was 3770 rpm what is the magnitude of its angular deceleration Give answer in rev s2 Do not enter unit 5 37 You are correct Your receipt no is 156 3913 How many revolutions did the centrifuge complete after being turned off Do not enter unit 368 You are correct Your receipt no is 156 4743 The tub of a washer goes into its spin cycle starting from rest and gaining angular speed steadily for 8 67 s when it is turning at 4 76 rev s At this point the person doing the laundry opens the lid and a safety switch turns off the washer The tub smoothly slows to rest in 12 3 s Through how many revolutions does the tub turn while it is in motion Do not enter units 49 9 You are correct Your receipt no is 156 9534 When it is 5 00 the hour hand on an analog clock is 150 ahead of the minute hand How many minutes elapse to three significant digits before the minute hand next points in the same direction as the hour hand 27 27 min You are correct Your receipt no is 156 2434 A 15 0 g CD with a radius of 5 93 cm rotates with an angular speed of 30 5 rad s What is its kinetic energy 0 123 J You are correct Your receipt no is 156 9885 What angular speed must the CD have if its kinetic energy is to be doubled 43 1 rad s You are correct Your receipt no is 156 430 What linear speed must a 0 0504 kg hula hoop have if its total kinetic energy is to be 0 183 J Assume the hoop rolls on the ground without slipping 1 91 m s You are correct Your receipt no is 156 218 PHYS 1111 Intro Physics I Mechanics Nguyen Spring 2015 Homework 09 Daniel Hernandez Printed from LON CAPA MSU Licensed under GNU General Public License
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