Energy of a system

Energy of a system - adamkiewicz (ja28724) Energy of a...

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: adamkiewicz (ja28724) Energy of a system Morozova (11102) 1 This print-out should have 12 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0 points This question is typical on some drivers li- cense exams: A car moving at 43 km / h skids 13 m with locked brakes. How far will the car skid with locked brakes at 107 . 5 km / h? Correct answer: 81 . 25 m. Explanation: 107 . 5 km / h 43 km / h = 2 . 5 At 2 . 5 times the speed, it has 6 . 25 times the KE parenleftbigg 1 2 m v 2 parenrightbigg and will skid 6 . 25 times as far: 81 . 25 m. Since the frictional force is about the same in both cases, the distance has to be 6 . 25 times as great for 6 . 25 times as much work done by the pavement on the car. 002 10.0 points The Joule and the kilowatt-hour are both units of energy. 11 . 9 kW h is equivalent to how many Joules? Correct answer: 4 . 284 10 7 J. Explanation: 1 W = 1 J / s 11 . 9 kW h = (11 . 9 kW h) 1000 W kW 3600 s 1 h = 4 . 284 10 7 W s = 4 . 284 10 7 J . 003 (part 1 of 5) 10.0 points A 18 . 9 kg block is dragged over a rough, hor- izontal surface by a constant force of 118 N acting at an angle of angle 31 above the hor- izontal. The block is displaced 48 . 2 m, and the coefficient of kinetic friction is 0 . 203....
View Full Document

This note was uploaded on 04/14/2009 for the course PHYS 111 taught by Professor Moro during the Spring '08 term at NJIT.

Page1 / 3

Energy of a system - adamkiewicz (ja28724) Energy of a...

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