/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 5 The data in the following table ... [FREE SOLUTION] | 91Ó°ÊÓ

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The data in the following table describe the initial and final positions of a moving car. The elapsed time for each of the three pairs of positions listed in the table is 0.50 s. Review the concept of average velocity in Section 2.2 and then determine the average velocity (magnitude and direction) for each of the three pairs. Note that the algebraic sign of your answers will convey the direction. $$\begin{array}{lcc} & \text { Initial position } x_{0} & \text { Final position } x \\\\\hline \text { (a) } & +2.0 \mathrm{m} & +6.0 \mathrm{m} \\\\\hline \text { (b) } & +6.0 \mathrm{m} & +2.0\mathrm{m} \\\\\hline \text { (c) } & -3.0 \mathrm{m} & +7.0 \mathrm{m} \\\\\hline\end{array}$$

Short Answer

Expert verified
(a) +8.0 m/s, (b) -8.0 m/s, (c) +20.0 m/s.

Step by step solution

01

Understanding Average Velocity

The formula for average velocity \( v_{\text{avg}} \) is given by \( v_{\text{avg}} = \frac{\Delta x}{\Delta t} \), where \( \Delta x \) is the change in position and \( \Delta t \) is the change in time.
02

Calculate \( \Delta x \) for Each Pair

For each scenario, the change in position \( \Delta x \) can be found by subtracting the initial position \( x_0 \) from the final position \( x \).
03

Compute Average Velocity for Pair (a)

For part (a), the initial position \( x_0 = +2.0 \ \mathrm{m} \) and the final position \( x = +6.0 \ \mathrm{m} \). Thus, \( \Delta x = 6.0 - 2.0 = 4.0 \ \mathrm{m} \). The time interval \( \Delta t = 0.50 \ \mathrm{s} \). Applying the formula: \[ v_{\text{avg}} = \frac{\Delta x}{\Delta t} = \frac{4.0 \ \mathrm{m}}{0.50 \ \mathrm{s}} = 8.0 \ \mathrm{m/s} \] The positive sign indicates movement in the positive direction.
04

Compute Average Velocity for Pair (b)

For part (b), the initial position \( x_0 = +6.0 \ \mathrm{m} \) and the final position \( x = +2.0 \ \mathrm{m} \). Thus, \( \Delta x = 2.0 - 6.0 = -4.0 \ \mathrm{m} \). The time interval \( \Delta t = 0.50 \ \mathrm{s} \). Applying the formula: \[ v_{\text{avg}} = \frac{\Delta x}{\Delta t} = \frac{-4.0 \ \mathrm{m}}{0.50 \ \mathrm{s}} = -8.0 \ \mathrm{m/s} \] The negative sign indicates movement in the negative direction.
05

Compute Average Velocity for Pair (c)

For part (c), the initial position \( x_0 = -3.0 \ \mathrm{m} \) and the final position \( x = +7.0 \ \mathrm{m} \). Thus, \( \Delta x = 7.0 - (-3.0) = 10.0 \ \mathrm{m} \). The time interval \( \Delta t = 0.50 \ \mathrm{s} \). Applying the formula: \[ v_{\text{avg}} = \frac{\Delta x}{\Delta t} = \frac{10.0 \ \mathrm{m}}{0.50 \ \mathrm{s}} = 20.0 \ \mathrm{m/s} \] The positive sign indicates movement in the positive direction.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Change in Position
Change in position, often represented by the symbol \( \Delta x \), is a fundamental concept in understanding motion. It refers to the difference between the final and initial positions of an object. This measurement helps determine how far and in what direction an object has traveled during its movement. When calculating the change in position, use the formula: - \( \Delta x = x - x_0 \) - Where \( x \) is the final position - \( x_0 \) is the initial position.For instance, if a car moves from \( +2.0 \, \mathrm{m} \) to \( +6.0 \, \mathrm{m} \), the change in position would be \( 6.0 - 2.0 = 4.0 \, \mathrm{m} \). This represents a movement in the positive direction, as indicated by the positive sign of the result. Understanding this concept is crucial since it provides the foundational step needed to compute the average velocity of any moving object.
Elapsed Time
Elapsed time, denoted by \( \Delta t \), is the total time taken for an object to travel from its initial position to its final position. This concept is essential when calculating average velocity because velocity examines changes over a time duration.To find the elapsed time, we often need to determine how many seconds, or another unit of time, pass during the object's journey. Given that elapsed time is vital for determining speed or velocity, accuracy in measuring it is paramount.In exercises like the one given, where the elapsed time for each situation is consistently \( 0.50 \, \mathrm{s} \), it simplifies the task of calculating average velocity because time does not need individual determination for each scenario. This consistency allows you to focus on other variables that influence the results.
Direction of Velocity
Direction of velocity is a critical aspect because it does not only define how fast an object moves but also where it's headed. The direction is usually conveyed through the sign of the velocity value. For example, in typical coordinate systems:- A positive velocity indicates movement in the positive direction.- A negative velocity signals movement in the opposite or negative direction.For example, when calculating average velocity, keep the signs in mind. If you obtain a result like \( 8.0 \, \mathrm{m/s} \), it suggests the object moved forward in the positive direction. Conversely, a result of \( -8.0 \, \mathrm{m/s} \) implies the object travelled backward or in the negative direction.Direction is as important as magnitude because it provides a comprehensive understanding of the object's motion. Always consider both aspects when evaluating physical motion problems.

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Most popular questions from this chapter

A model rocket blasts off from the ground, rising straight upward with a constant acceleration that has a magnitude of \(86.0 \mathrm{m} / \mathrm{s}^{2}\) for 1.70 seconds, at which point its fuel abruptly runs out. Air resistance has no effect on its flight. What maximum altitude (above the ground) will the rocket reach?

An Australian emu is running due north in a straight line at a speed of \(13.0 \mathrm{m} / \mathrm{s}\) and slows down to a speed of \(10.6 \mathrm{m} / \mathrm{s}\) in \(4.0 \mathrm{s}\). (a) What is the direction of the bird's acceleration? (b) Assuming that the acceleration remains the same, what is the bird's velocity after an additional \(2.0 \mathrm{s}\) has elapsed?

One afternoon, a couple walks three-fourths of the way around a circular lake, the radius of which is \(1.50 \mathrm{km}\). They start at the west side of the lake and head due south to begin with. (a) What is the distance they travel? (b) What are the magnitude and direction (relative to due east) of the couple's displacement?

A jetliner, traveling northward, is landing with a speed of \(69 \mathrm{m} / \mathrm{s}\). Once the jet touches down, it has \(750 \mathrm{m}\) of runway in which to reduce its speed to \(6.1 \mathrm{m} / \mathrm{s} .\) Compute the average acceleration (magnitude and direction) of the plane during landing.

The space shuttle travels at a speed of about \(7.6 \times 10^{3} \mathrm{m} / \mathrm{s} .\) The blink of an astronaut's eye lasts about \(110 \mathrm{ms}\). How many football fields (length \(=91.4 \mathrm{m})\) does the shuttle cover in the blink of an eye?

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