# Straight line, "fractional difference"

by CarEnthusiast
Tags: line, straight
 P: 1 1. The problem statement, all variables and given/known data To set a speed record in measured (straight) distance d, a race car must be driven first in one direction (in time t1) and then in the opposite direction (in time t2). (a) To eliminate the effects of the wind and obtain the car's speed vc in a windless situation, should we find the average of d/t1 and d/t2 (method 1) or should we divide d by the average of t1 and t2? (b) What is the fractional difference in the two methods when a steady wind blows along the car's route and the ratio of the wind speed vw to the car's speed vc is 0.0240? 2. Relevant equations t1 = with wind t2 = against wind v1 = d/t1 v2 = d/t2 v1 = vc+0.0240vc v2 = vc-0.0240vc "Method 1": vc = (v1+v2)/2 "Method 2": vc = d/(1/2(t1+t2)) 3. The attempt at a solution I understand the principle behind the problem (the physics concept is easy), but I cannot understand how one method is better than the other if they end up equaling the same thing. Also, where does the "fractional difference" come in, and how do you calculate it?
 P: 44 Do they really "end up equalling the same thing"? You certainly haven't shown that they do - perhaps you should try to manipulate your answers to "Method 1" and "Method 2" to check whether or not this is true. The "fractional difference" between two numbers is the difference between them divided by the "reference" number - which in this case would be whichever of the two methods correctly predicts the windless speed. (I.e., $$\frac{\text{other method} - \text{windless speed}}{\text{windless speed}}$$ )

 Related Discussions Introductory Physics Homework 5 General Physics 15 Special & General Relativity 23 Calculus & Beyond Homework 9 Introductory Physics Homework 2
The text passage contains a physics problem that involves a mathematical question about calculating the speed of a race car in a windless situation using two different methods, and it asks for the fractional difference between these methods when a wind is present. The passage also includes an attempt at a solution and a response from another user suggesting how to proceed.
single_question_with_answer
Given a text passage, determine:
    1. If it contains a mathematical question (including word problems or calculations)
    2. If an answer to that mathematical question is provided in the text

First, describe the content structure you found in 1-2 sentences.

Then provide your analysis in the following format:
TYPE: <one of the following values>
- NO_QUESTION
- SINGLE_QUESTION
- SINGLE_QUESTION_WITH_ANSWER
- MULTIPLE_QUESTIONS
- MULTIPLE_QUESTIONS_WITH_ANSWERS
system
# Straight line, "fractional difference"

by CarEnthusiast
Tags: line, straight
 P: 1 1. The problem statement, all variables and given/known data To set a speed record in measured (straight) distance d, a race car must be driven first in one direction (in time t1) and then in the opposite direction (in time t2). (a) To eliminate the effects of the wind and obtain the car's speed vc in a windless situation, should we find the average of d/t1 and d/t2 (method 1) or should we divide d by the average of t1 and t2? (b) What is the fractional difference in the two methods when a steady wind blows along the car's route and the ratio of the wind speed vw to the car's speed vc is 0.0240? 2. Relevant equations t1 = with wind t2 = against wind v1 = d/t1 v2 = d/t2 v1 = vc+0.0240vc v2 = vc-0.0240vc "Method 1": vc = (v1+v2)/2 "Method 2": vc = d/(1/2(t1+t2)) 3. The attempt at a solution I understand the principle behind the problem (the physics concept is easy), but I cannot understand how one method is better than the other if they end up equaling the same thing. Also, where does the "fractional difference" come in, and how do you calculate it?
 P: 44 Do they really "end up equalling the same thing"? You certainly haven't shown that they do - perhaps you should try to manipulate your answers to "Method 1" and "Method 2" to check whether or not this is true. The "fractional difference" between two numbers is the difference between them divided by the "reference" number - which in this case would be whichever of the two methods correctly predicts the windless speed. (I.e., $$\frac{\text{other method} - \text{windless speed}}{\text{windless speed}}$$ )

 Related Discussions Introductory Physics Homework 5 General Physics 15 Special & General Relativity 23 Calculus & Beyond Homework 9 Introductory Physics Homework 2
user
The text passage contains a physics problem that involves a mathematical question about calculating the speed of a race car in a windless situation using two different methods, and it asks for the fractional difference between these methods when a wind is present. The passage also includes an attempt at a solution and a response from another user suggesting how to proceed.

TYPE: SINGLE_QUESTION_WITH_ANSWER