HW 4 - Morgan, Mena – Homework 4 – Due: Oct 3 2007,...

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: Morgan, Mena – Homework 4 – Due: Oct 3 2007, 11:00 pm – Inst: Opyrchal, H 1 This print-out should have 9 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. The due time is Central time. 001 (part 1 of 1) 10 points An elevator starts from rest with a constant upward acceleration and moves 1 m in the first 1 . 4 s. A passenger in the elevator is holding a 5 . 5 kg bundle at the end of a vertical cord. The acceleration of gravity is 9 . 8 m / s 2 . What is the tension in the cord as the ele- vator accelerates? Correct answer: 59 . 5122 N. Explanation: T mg a elevator g Let h be the distance traveled and a the acceleration of the elevator. With the initial velocity being zero, we simplify the following expression and solve for acceleration of the elevator: h = v t + 1 2 at 2 = 1 2 at 2 = ⇒ a = 2 h t 2 . The equation describing the forces acting on the bundle is F net = ma = T- mg T = m ( g + a ) = m µ g + 2 h t 2 ¶ = (5 . 5 kg) • 9 . 8 m / s 2 + 2 (1 m) (1 . 4 s) 2 ‚ = 59 . 5122 N . keywords: 002 (part 1 of 1) 10 points Two forces are the only forces acting on a 3 . 1 kg object which moves with an accelera- tion of 2 . 7 m / s 2 in the positive y direction. One of the forces acts in the positive x direc- tion and has a magnitude of 14 N. What is the magnitude of the other force f 2 ? Correct answer: 16 . 3113 N....
View Full Document

This note was uploaded on 04/07/2012 for the course PHYSICS 121 taught by Professor James during the Spring '12 term at University of Texas.

Page1 / 4

HW 4 - Morgan, Mena – Homework 4 – Due: Oct 3 2007,...

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