hw14 - khounvivongsy (sk27799) Homework 14 Weathers (17104)...

Info iconThis preview shows pages 1–3. 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: khounvivongsy (sk27799) Homework 14 Weathers (17104) 1 This print-out should have 13 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0 points The speed of a moving bullet can be deter- mined by allowing the bullet to pass through two rotating paper disks mounted a distance 98 cm apart on the same axle. From the angular displacement 21 of the two bullet holes in the disks and the rotational speed 821 rev / min of the disks, we can determine the speed of the bullet. 21 v 821 rev / min 98 cm What is the speed of the bullet? Correct answer: 229 . 88 m / s. Explanation: Let : = 821 rev / min , d = 98 cm , and = 21 . = t t = , so the speed of the bullet is v = d t = d = (98 cm) (821 rev / min) 21 360 1 rev 1 m 100 cm 1 min 60 s = 229 . 88 m / s . keywords: 002 10.0 points A wheel starts from rest at t = 0 and rotates with a constant angular acceleration about a fixed axis. It completes the first revolution in 2 . 9 s. How long after t = 0 will the wheel com- plete the second revolution? Correct answer: 4 . 10122 s. Explanation: Let : t 1 = 2 . 9 s , 1 = 1 rev , and 2 = 2 rev . The wheel starts from rest, so = + 1 2 t 2 = 1 2 t 2 t 2 . Thus 2 1 = t 2 2 t 2 1 t 2 = radicalbigg 2 1 t 1 = radicalbigg 2 rev 1 rev (2 . 9 s) = 4 . 10122 s . 003 10.0 points A bicycle is turned upside down while its owner repairs a flat tire. A friend spins the other wheel of radius 0 . 4 m and observes that drops of water fly off tangentially. She mea- sures the height reached by drops moving ver- tically. A drop that breaks loose from the tire on one turn rises 83 . 8 cm above the tangent point. A drop that breaks loose on the next turn rises 81 . 7 cm above the tangent point khounvivongsy (sk27799) Homework 14 Weathers (17104) 2 (the angular speed of the wheel is decreas- ing). h . 4 m radius Find the angular deceleration of the wheel. The acceleration of gravity is 9 . 8 m / s 2 . As- sume the angular deceleration is constant....
View Full Document

Page1 / 6

hw14 - khounvivongsy (sk27799) Homework 14 Weathers (17104)...

This preview shows document pages 1 - 3. Sign up to view the full document.

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