/*! 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 100 An iceboat sails across the surf... [FREE SOLUTION] | 91Ó°ÊÓ

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An iceboat sails across the surface of a frozen lake with constant acceleration produced by the wind. At a certain instant the boat's velocity is \((6.30 \hat{\mathrm{i}}-8.42 \mathrm{j}) \mathrm{m} / \mathrm{s}\). Three seconds later, because of a wind shift, the boat is instantaneously at rest. What is its average acceleration for this \(3,00 \mathrm{~s}\) interval?

Short Answer

Expert verified
The average acceleration is \((-2.10\hat{\mathrm{i}} + 2.81\hat{\mathrm{j}})\, m/s^2\).

Step by step solution

01

Understand the Given Information

The problem states that an iceboat moves with constant acceleration and at a certain moment has a velocity \( \mathbf{v_i} = (6.30\hat{\mathbf{i}} - 8.42\hat{\mathbf{j}}) \; m/s \). Three seconds later, the boat comes to rest, meaning its final velocity \( \mathbf{v_f} = (0\hat{\mathbf{i}} + 0\hat{\mathbf{j}}) \; m/s \). The time interval is \( \Delta t = 3.00 \; s \). We need to find the average acceleration during this interval.
02

Use the Formula for Average Acceleration

The formula for average acceleration \( \mathbf{a_{avg}} \) is given by the change in velocity divided by the time interval, \( \mathbf{a_{avg}} = \frac{\Delta \mathbf{v}}{\Delta t} \). Here, the change in velocity \( \Delta \mathbf{v} = \mathbf{v_f} - \mathbf{v_i} \).
03

Calculate the Change in Velocity

Substitute the initial and final velocities into the expression for change in velocity: \( \Delta \mathbf{v} = (0\hat{\mathbf{i}} + 0\hat{\mathbf{j}}) - (6.30\hat{\mathbf{i}} - 8.42\hat{\mathbf{j}}) \).This results in \( \Delta \mathbf{v} = (-6.30\hat{\mathbf{i}} + 8.42\hat{\mathbf{j}}) \; m/s \).
04

Compute the Average Acceleration

Substitute \( \Delta \mathbf{v} \) and \( \Delta t \) into the average acceleration formula: \[ \mathbf{a_{avg}} = \frac{-6.30\hat{\mathbf{i}} + 8.42\hat{\mathbf{j}}}{3.00} \].Calculating each component gives: - \( a_{avg\_i} = \frac{-6.30}{3.00} = -2.10 \; m/s^2 \)- \( a_{avg\_j} = \frac{8.42}{3.00} \approx 2.81 \; m/s^2 \)Thus, the average acceleration is \( \mathbf{a_{avg}} = (-2.10\hat{\mathbf{i}} + 2.81\hat{\mathbf{j}}) \; m/s^2 \).

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Key Concepts

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

Constant Acceleration
A key concept in many physics problems, constant acceleration indicates that an object's velocity changes at a steady rate over time. This means the object's velocity increases or decreases in equal amounts over equal time intervals.
This concept is essential because it simplifies calculations, allowing us to predict future motion easily.
  • Imagine a car accelerating in a straight line; if it speeds up by the same amount each second, it's experiencing constant acceleration.
  • Similarly, in our iceboat problem, even though the boat eventually stops, it experiences constant acceleration as its velocity smoothly decreases to zero.
Understanding constant acceleration helps us model real-world phenomena using simple mathematical formulas, like the average acceleration formula used in the exercise. In this way, the real-world actions become manageable through predictable calculations.
Velocity Change
Velocity change is the difference between the final velocity and the initial velocity of an object. In physics, this change can occur due to various factors like applied forces or changes in direction.
  • In our iceboat exercise, the velocity change occurs due to wind, which affects the boat's motion on the ice.
  • The initial and final vectors describe the boat's motion, making it a challenge to resolve the components of velocity.
The change in velocity is crucial when calculating average acceleration, as it's necessary to determine the total shift in speed and direction over a given time. This is mathematically expressed as \[\Delta \mathbf{v} = \mathbf{v_f} - \mathbf{v_i}\] where \(\mathbf{v_f}\) and \(\mathbf{v_i}\) are the final and initial velocities respectively. Mastery of this concept allows for accurate predictions of motion in varying contexts.
Vector Calculation
Vector calculation involves handling the magnitudes and directions of vectors, which are essential in describing quantities like velocity and acceleration. In many physics problems, such as the ones dealing with motion in two or three dimensions, vectors help to break down these quantities easily.
  • Vectors are often split into components, such as the \(\hat{\mathbf{i}}\) and \(\hat{\mathbf{j}}\) used to depict east-west and north-south directions, respectively.
  • This method allows us to work with each direction independently before combining the results to get a holistic understanding of the motion.
In the iceboat exercise, the vectors are split into horizontal and vertical components to facilitate understanding. By subtracting each respective component of the initial vector from the final vector, we determine the vector of change.
This systematic approach of working through vector components ensures accurate and insightful analysis of physical problems.
Time Interval Calculation
Time interval calculation is about determining the time period over which a particular motion or change occurs. It's a fundamental aspect of kinematics, as it helps in calculating other dynamic variables like velocity and acceleration.
  • In physics, constant acceleration or velocity change cannot be fully understood without considering the time over which these changes take place.
  • This is because the rate of change is expressed in terms of time, making the time interval crucial for understanding dynamic scenarios.
For instance, in the problem of the iceboat, knowing that the boat comes to rest takes precisely 3 seconds allows us to calculate how quickly it decelerates. By fitting this time interval into our formulas, such as the average acceleration formula, the calculations become grounded in reality with a time-bound context: \[\mathbf{a_{avg}} = \frac{\Delta \mathbf{v}}{\Delta t}\] Understanding and calculating time intervals effectively bridges the gap between theoretical equations and real-world applications of motion.

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Most popular questions from this chapter

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