solution-hw15

solution-hw15 - lai (yl8859) HW15 Ross (15200) 1 This...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: lai (yl8859) HW15 Ross (15200) 1 This print-out should have 11 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 (part 1 of 3) 10.0 points As a result of friction, the angular speed of a wheel c hanges with time according to d d t = e t , where and are constants. The angular speed changes from an initial angular speed of 5 . 53 rad / s to 4 . 73 rad / s in 3 . 92 s . Determine the magnitude of the angular acceleration after 1 . 88 s. Correct answer: 0 . 204525 rad / s 2 . Explanation: Let : = 5 . 53 rad / s , t = 0 , 2 = 4 . 73 rad / s , t 2 = 3 . 92 s , and t 3 = 1 . 88 s . The equation of motion is = e t , so 2 = e t 2 ln parenleftbigg 2 parenrightbigg = t 2 = ln parenleftbigg 2 parenrightbigg t 2 = ln parenleftbigg 4 . 73 rad / s 5 . 53 rad / s parenrightbigg 3 . 92 s = 0 . 0398629 s 1 . Thus the angular acceleration at t 3 is ( t 3 ) = d dt = ( ) e t 3 = (5 . 53 rad / s) (0 . 0398629 s 1 ) e (0 . 0398629 s- 1 ) (1 . 88 s) = . 204525 rad / s 2 bardbl vector ( t 3 ) bardbl = . 204525 rad / s 2 . 002 (part 2 of 3) 10.0 points How many revolutions does the wheel make after 1 . 15 s ? Correct answer: 0 . 989296 rev. Explanation: Let : t f = 1 . 15 s . = integraldisplay t f e t dt = integraldisplay t f e t ( dt ) = e t vextendsingle vextendsingle vextendsingle...
View Full Document

This note was uploaded on 02/24/2011 for the course PHYS 152 taught by Professor Button during the Winter '08 term at IUPUI.

Page1 / 4

solution-hw15 - lai (yl8859) HW15 Ross (15200) 1 This...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online