1169060996Xuj

1169060996Xuj - Alvarado, Patrick Homework 2 Due: Sep 21...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Alvarado, Patrick – Homework 2 – Due: Sep 21 2006, 10:00 am – Inst: Andrei Sirenko 1 This print-out should have 22 questions. Multiple-choice questions may continue on the next column or page – fnd all choices beFore answering. The due time is Central time. 001 (part 1 oF 1) 10 points Nobody at the playground wants to play with an obnoxious boy, so he Fashions a seesaw as shown so he can play by himselF. Explain how this is done. 1. The angular velocity oF the boy is can- celled with that oF the board. 2. The weight oF the boy is balanced with an unknown heavy metal. 3. The weight oF the boy is balanced by the weight oF the board. correct 4. The Fulcrum is very Far From the boy. Explanation: The weight oF the boy is counterbalanced by the weight oF the board, which can be consid- ered to be concentrated at its center oF gravity on the opposite side oF the Fulcrum. He is in balance when his weight multiplied by his dis- tance From the Fulcrum is equal to the weight oF the entire board multiplied by the distance between the Fulcrum and the midpoint (center oF gravity) oF the board. (How do the relative weight oF boy and board relate to the relative lever arms?) keywords: 002 (part 1 oF 1) 10 points The net work done in accelerating a propeller From rest to an angular speed oF 306 rad / s is 1864 J. What is the moment oF inertia oF the pro- peller? Correct answer: 0 . 0398137 kg · m 2 . Explanation: Given : W = 1864 J and ω = 306 rad / s . Using W = Δ K = K f - K i = 1 2 I ω 2 - 0 , we get I = 2 W ω 2 = 2 (1864 J) (306 rad / s) 2 , = 0 . 0398137 kg · m 2 . keywords: 003 (part 1 oF 1) 10 points Consider the diatomic molecule oxygen, O 2 , which is rotating in the xy plane about the z axis passing through its center, perpendicular to its length. The mass oF each oxygen atom is 2 . 66 × 10 - 26 kg, and at room temperature, the average separation distance between the two oxygen atoms is 2 . 68 × 10 - 10 m(the atoms are treated as point masses). IF the angular speed oF the molecule about the z axis is 3 . 55 × 10 12 rad / s, what is its rotational kinetic energy? Correct answer: 6 . 01933 × 10 - 21 J. Explanation: Since the distance oF each atom Form the z axis is d/ 2 (where d = 2 . 68 × 10 - 10 m is the separation distance between the two oxygen atoms), the moment oF inertial about the z axis is I = 2 X n =1 m n r 2 n = m µ d 2 2 + m µ d 2 2 = 1 2 md 2 , where m = 2 . 66 × 10 - 26 kg is the mass oF an oxygen atom. Using the Formula For the
Background image of page 1

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

View Full DocumentRight Arrow Icon
Alvarado, Patrick – Homework 2 – Due: Sep 21 2006, 10:00 am – Inst: Andrei Sirenko 2 rotational kinetic energy, we obtain K R = 1 2 I ω 2 = 1 4 md 2 ω 2 = 6 . 01933 × 10 - 21 J . keywords: 004 (part 1 of 2) 10 points Calculate the moment of inertia of a solid cylinder of mass 5 . 68 kg and radius 8 . 14 m about an axis parallel to the center-of-mass axis and passing through the edge of the cylin- der. (Use the parallel-axis theorem and Table 10.2) Correct answer: 564 . 532 kg m 2 . Explanation:
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/04/2008 for the course PHYS 106 taught by Professor Opyt during the Spring '08 term at NJIT.

Page1 / 8

1169060996Xuj - Alvarado, Patrick Homework 2 Due: Sep 21...

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