# hw6 - lenoir (wml297) homework 05 Turner (58220) 1 This...

This preview shows pages 1–3. 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: lenoir (wml297) homework 05 Turner (58220) 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 (part 1 of 3) 10.0 points Two cars are traveling along a straight line in the same direction, the lead car at 32 m / s and the other car at 44 m / s. At the moment the cars are 47 m apart, the lead driver applies the brakes, causing the car to have an acceleration of 1 . 6 m/s 2 . a) How long does it take for the lead car to stop? Correct answer: 20 s. Explanation: Basic Concept: a avg = v f v i t = v i t since v f = 0 m/s. Given: v i, 1 = +32 m / s v f, 1 = 0 m / s a 1 = 1 . 6 m / s 2 Solution: t 1 = v i, 1 a 1 = 32 m / s 1 . 6 m / s 2 = 20 s 002 (part 2 of 3) 10.0 points Assume that the driver of the chasing car applies the brakes at the same time as the driver of the lead car. b) What must the chasing cars minimum negative acceleration be to avoid hitting the lead car? Correct answer: 2 . 6376 m / s 2 . Explanation: Basic Concepts: The equations simplify to x = 1 2 ( v f + v i ) t = v i 2 t and 0 = v 2 i + 2 a x since v f = 0 m/s. Given: v i, 2 = +44 m / s v f, 2 = 0 m / s x 2 = x 1 + 47 m t 2 = t 1 = 20 s Solution: The lead car traveled x 1 = 32 m / s 2 (20 s) = 320 m The chasing car traveled x 2 = 320 m + 47 m = 367 m with a minimum acceleration of a 2 = v 2 i, 2 2 x 2 = (44 m / s) 2 2(367 m) = 2 . 6376 m / s 2 003 (part 3 of 3) 10.0 points c) How long does it take the chasing car to stop? Correct answer: 16 . 6818 s. Explanation: Basic Concepts: a = v f v i t = v i t since v f = 0 m/s. Given: v i, 2 = 44 m / s a 2 = 2 . 6376 m / s 2 Solution: t 2 = v i, 2 a 2 = 44 m / s 2 . 6376 m / s 2 = 16 . 6818 s lenoir (wml297) homework 05 Turner (58220) 2 004 (part 1 of 2) 10.0 points Throw a ball upward from point O with an initial speed of 70 m / s....
View Full Document

## This note was uploaded on 04/15/2010 for the course PHY 12343 taught by Professor Turner during the Spring '10 term at University of Texas at Austin.

### Page1 / 5

hw6 - lenoir (wml297) homework 05 Turner (58220) 1 This...

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

View Full Document
Ask a homework question - tutors are online