/*! 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 52 An object initially at rest expe... [FREE SOLUTION] | 91Ó°ÊÓ

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An object initially at rest experiences an acceleration of \(2.00 \mathrm{~m} / \mathrm{s}^{2}\) on a level surface. Under these conditions, it travels \(6.00 \mathrm{~m}\). Let's designate the first \(3.00 \mathrm{~m}\) as phase 1 with a subscript of 1 for those quantities, and the second \(3.00 \mathrm{~m}\) as phase 2 with a subscript of \(2 .\) (a) The times for traveling each phase should be related by which condition: (3) \(t_{1}>t_{2} ?\) (b) Now calculate the (1) \(t_{1}

Short Answer

Expert verified
The times satisfy \( t_1 > t_2 \).

Step by step solution

01

Identify Given Values

The object starts at rest, so its initial velocity \( u = 0 \). The acceleration \( a = 2.00 \text{ m/s}^2 \). The total displacement is divided into two phases: \( s_1 = 3.00 \text{ m} \) for phase 1 and \( s_2 = 3.00 \text{ m} \) for phase 2.
02

Use Kinematic Equation for Each Phase

The kinematic equation that relates distance \( s \), initial velocity \( u \), time \( t \), and acceleration \( a \) is: \[ s = ut + \frac{1}{2}at^2. \] Since the object starts from rest, \( u = 0 \), so it simplifies to \( s = \frac{1}{2}at^2 \).
03

Calculate Time for Phase 1

Using \( s_1 = 3.00 \text{ m} \) and \( a = 2.00 \text{ m/s}^2 \), \[ 3.00 = \frac{1}{2} \times 2.00 \times t_1^2. \] Solve for \( t_1 \) by rearranging: \[ t_1^2 = \frac{3.00}{1.00} = 3.00, \]\[ t_1 = \sqrt{3.00} \approx 1.73 \text{ s}. \]
04

Calculate Time for Phase 2

During the second phase, the object starts with an initial velocity obtained at the end of phase 1. First, find the final velocity after phase 1 using \( v = u + at \),\[ v_1 = 0 + 2.00 \times 1.73 \approx 3.46 \text{ m/s}. \]For phase 2, use \( s_2 = 3.00 \text{ m} \), \( a = 2.00 \text{ m/s}^2 \), and \( u = 3.46 \text{ m/s} \),\[ 3.00 = 3.46t_2 + \frac{1}{2} \times 2.00 \times t_2^2. \]Rearrange to form a quadratic equation,\[ t_2^2 + 3.46t_2 - 3.00 = 0. \]
05

Solve the Quadratic Equation for Phase 2

Use the quadratic formula, \( t = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \), where \( a = 1, b = 3.46, c = -3.00 \),\[ t_2 = \frac{-3.46 \pm \sqrt{3.46^2 + 4 \times 3.00}}{2}. \]Calculate the discriminant and solutions,\[ t_2 = \frac{-3.46 \pm \sqrt{11.97 + 12.00}}{2}, \]\[ t_2 = \frac{-3.46 \pm \sqrt{23.97}}{2}. \]The relevant solution is \[ t_2 = \frac{-3.46 + 4.89}{2} \approx 0.715 \text{ s}. \]
06

Compare the Travel Times

From the calculations, \( t_1 = 1.73 \text{ s} \) and \( t_2 = 0.715 \text{ s} \).Therefore, \( t_1 > t_2 \).
07

Conclusion: Condition Satisfaction

Based on the calculations, the travel times satisfy the condition \( t_1 > t_2 \). Thus, the object's acceleration makes it travel quicker over equal distances as its velocity increases.

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Key Concepts

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

Acceleration
Acceleration is a fundamental concept in kinematics that describes how quickly an object's velocity changes over time. In this exercise, the object experiences an acceleration of \(2.00 \, \text{m/s}^2\), meaning its velocity increases by 2 meters per second every second. Acceleration is a vector quantity, which means it has both magnitude and direction. - Positive acceleration indicates an increase in velocity. - Negative acceleration (deceleration) indicates a decrease in velocity. In many kinematics problems, acceleration is assumed constant, allowing us to use certain kinematic equations. Understanding acceleration is crucial to solving problems related to motion, as it directly affects how an object's speed changes as it travels different distances.
Displacement
Displacement refers to the change in position of an object. It’s a vector quantity, which means it includes both distance and direction from the starting point. In the problem, displacement is divided into two segments: phase 1 and phase 2, each 3.00 meters long, totaling 6.00 meters. This makes it manageable to calculate the time taken for each segment separately. Displacement is crucial in determining how far an object has moved during a certain period, which then helps in calculating the time taken or velocity if other parameters, like acceleration, are known. When measuring displacement, it's important to remember: - Displacement is different from distance. Distance is scalar and refers to the total path covered. - Displacement considers only the net change in position, not the path taken.
Kinematics
Kinematics is the branch of physics that deals with the motion of objects, without considering the causes of this motion (like forces). When analyzing motion, kinematics focuses on measurable quantities such as velocity, acceleration, displacement, and time.Primary kinematic equations let you relate different motion aspects, such as:- Distance \(s\). - Initial velocity \(u\). - Time \(t\). - Acceleration \(a\). - Final velocity \(v\).These equations assume uniform acceleration, which simplifies calculations:- \( v = u + at \) represents the final velocity. - \( s = ut + \frac{1}{2}at^2 \) relates distance, time, and acceleration.- \( v^2 = u^2 + 2as \) determines the velocity based on displacement and acceleration. Kinematics allows us to predict how moving objects behave over time, which is invaluable in fields like engineering and physics.
Quadratic Equations
Quadratic equations appear frequently in physics problems involving kinematics, especially when dealing with objects in motion under constant acceleration. The general form of a quadratic equation is:\[ ax^2 + bx + c = 0 \]In this exercise, finding the time duration for phase 2 involves solving such an equation:\[ t_2^2 + 3.46t_2 - 3.00 = 0 \]The quadratic formula \( t = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \) provides the solution for \(t_2\), giving us the time required. Quadratic equations can have two solutions; however, in physical problems, sometimes one solution might be irrelevant (like a negative time in this case). Knowing how to use and solve these equations is crucial in analyzing motion, particularly when multiple forces and parameters affect an object's trajectory.

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Most popular questions from this chapter

Many highways with steep downhill areas have "runaway truck" inclined paths just off the main roadbed. These paths are designed so that if a vehicle's braking system gives out, the driver can steer it onto this incline (usually composed of loose gravel or sand). The idea is that the vehicle can then roll up the incline and come permanently and safely to rest with no need of a braking system. In one region of Hawaii the incline distance is \(300 \mathrm{~m}\) and provides a (constant) deceleration of \(2.50 \mathrm{~m} / \mathrm{s}^{2}\). (a) What is the maximum speed that a runaway vehicle can have as it enters the incline? (b) How long would such a vehicle take to come to rest? (c) Suppose another vehicle moving \(10 \mathrm{mi} / \mathrm{h}(4.47 \mathrm{~m} / \mathrm{s})\) faster than the maximum value enters the incline. What speed will it have as it leaves the gravel-filled area?

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