Physics HW8

# Physics HW8 - kim(jkk547 – HW08 – Tsoi –(58020 1 This...

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

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

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: kim (jkk547) – HW08 – Tsoi – (58020) 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 10.0 points Two weights attached to a uniform beam of mass 56 kg are supported in a horizontal po- sition by a pin and cable as shown in the figure. The acceleration of gravity is 9 . 8 m / s 2 . 22 kg 59 kg 2 . 6 m 8 . 4 m 45 ◦ 56 kg What is the tension in the cable which sup- ports the beam? Correct answer: 1 . 30013 kN. Explanation: Let : m = 56 kg , M 1 = 22 kg , M 2 = 59 kg , L 1 = 2 . 6 m , L 2 = 8 . 4 m , and θ = 45 ◦ . Basic Concepts: summationdisplay vector F = 0 summationdisplay vector τ = 0 . Solution: The sum of the torques about the pivot is T L 2 sin θ- mg L 2 2- M 1 gL 1- M 2 gL 2 = 0 Solving for the tension T T = mg L 2 2 + M 1 g L 1 + M 2 g L 2 L 2 sin θ = (56 kg)(9 . 8 m / s 2 ) parenleftbigg 8 . 4 m 2 parenrightbigg (8 . 4 m) sin θ + (22 kg)(9 . 8 m / s 2 )(2 . 6 m) (8 . 4 m) sin θ + (59 kg)(9 . 8 m / s 2 )(8 . 4 m) (8 . 4 m) sin θ = 1 . 30013 kN . 002 (part 1 of 5) 10.0 points A child weighing 38 N climbs onto the right end of a see-saw, little knowing that it is tied down with a rope at its left end. The see-saw is 2 . 6 m long, weighs 12 N and is tilted at an angle of 17 ◦ from the horizontal. The center of mass of the see-saw is half way along its length, and lies right above the pivot. l θ What torque does the weight of the child exert about the pivot point? Take counter- clockwise to be positive. Correct answer:- 47 . 2415 N m....
View Full Document

## This note was uploaded on 10/04/2009 for the course PHY 58020 taught by Professor Tsoi during the Fall '09 term at University of Texas.

### Page1 / 5

Physics HW8 - kim(jkk547 – HW08 – Tsoi –(58020 1 This...

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

View Full Document
Ask a homework question - tutors are online