/*! 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 76 The Stratosphere Tower in Las Ve... [FREE SOLUTION] | 91Ó°ÊÓ

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The Stratosphere Tower in Las Vegas is 921 feet tall and has a "needle" at its top that extends even higher into the air. A thrill ride called Big Shot catapults riders 160 feet up the needle and then lets them fall back to the launching pad. a. The height \(h\) (in feet) of a rider on the Big Shot can be modeled by \(h=-16 t^2+v_0 t+921\), where \(t\) is the elapsed time (in seconds) after launch and \(v_0\) is the initial velocity (in feet per second). Find \(v_0\) using the fact that the maximum value of \(h\) is \(921+160=1081\) feet. b. A brochure for the Big Shot states that the ride up the needle takes 2 seconds. Compare this time to the time given by the model \(h=-16 t^2+v_0 t+921\), where \(v_0\) is the value you found in part (a). Discuss the accuracy of the model.

Short Answer

Expert verified
a) The initial speed of the ride is \(80 \, fps\). \n b) The model suggests it takes \(5\) seconds for the ride while the brochure states \(2\) seconds. Hence, the model is not accurate.

Step by step solution

01

Find the time at which maximum height is achieved

The maximum height is achieved at the vertex of the parabola. The time at which this occurs is given by \(-\frac{{v_0}}{{2(-16)}}\). This is derived from the formula \(-\frac{{b}}{{2a}}\) for the x-coordinate of the vertex of a parabola given by \(y = ax^2 + bx + c\). Here, \(a=-16\), \(b=v_0\), and \(c = 921\). Substituting these into the formula provides that \(t = \frac{{v_0}}{{32}}.\)
02

Calculate the initial velocity (\(v_0\))

The maximum height of \(1081\) feet is achieved when \(t = \frac{{v_0}}{{32}}\) seconds. Substituting these values into the height equation \(h = -16t^2 + v_0t + 921\) results in \(1081 = -16\left(\frac{{v_0}}{{32}}\right)^2 + v_0\left(\frac{{v_0}}{{32}}\right) + 921\). Simplifying this equation, we get \(v_0= \sqrt{16 \times 160} = 80 \, fps.\)
03

Compare the model time to the actual time

The time taken as given by the model when the initial velocity is \(80 \, fps\) is calculated by setting the height equation to \(921\) (i.e., when the rider gets back to the starting point). Solve the equation \(-16t^2 + 80t + 921 = 921\) for \(t\). We find \(t=5\). Thus, the model shows that the ride takes \(5\) seconds, while the brochure states it takes only \(2\) seconds. This shows that the model overestimates the time taken by the ride and is therefore not entirely accurate.

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Key Concepts

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

Vertex of a Parabola
In quadratic equations, the vertex of the parabola is a crucial point as it represents either the maximum or minimum value of the parabola's curve. This is determined based on the orientation of the parabola. For a parabola opening downward, like in this scenario, the vertex represents the maximum height. The formula to find the vertex for a quadratic equation in the form of \( y = ax^2 + bx + c \) is derived from \(-\frac{b}{2a}\). This gives us the x-coordinate of the vertex. In the context of parabolic motion, where the equation is \( h = -16t^2 + v_0t + 921 \), substituting \( a = -16 \) and \( b = v_0 \), the time \( t \) at which the maximum height is reached can be calculated as \( t = \frac{v_0}{32} \). Understanding this helps in analyzing when a projectile is at its peak height, a useful concept in physics and engineering.
Initial Velocity
Initial velocity, denoted as \( v_0 \), is the speed at which an object begins its motion. This parameter is pivotal in determining the projectile's trajectory. In the context of this exercise, we have a situation where the projectile—or in this case, the rider on the Big Shot—must reach a maximum height from a given starting point. Substituting the known values and the calculated time into the height equation \( h = -16t^2 + v_0t + 921 \), allows us to derive the initial velocity. Specifically, we found \( v_0 = \sqrt{16 \times 160} = 80 \) feet per second (fps). This initial speed determines how quickly the rider initially ascends and impacts the overall duration of ascent during the thrilling ride.
Parabolic Motion
Parabolic motion is a form of motion experienced by an object projected into the air, under the influence of gravity. The object follows a parabolic trajectory due to the constant acceleration due to gravity, acting downward. In the example of the thrill ride, we deal with vertical parabolic motion, described by the quadratic equation \( h = -16t^2 + v_0t + 921 \), where \( 16 \) represents half of the gravitational acceleration (assuming feet per second squared) and \( v_0 \) is the initial velocity. As time progresses, the object reaches a peak height and then descends back to the ground due to gravity. This elegant motion is what gives the thrill ride its name, as passengers experience a swift ascent followed by the exhilarating fall back to the earth, all following the natural laws of physics.
Height Equation
The height equation in this context expresses the vertical position \( h \) of a projectile at any given time \( t \) during its flight. Our specific height equation is \( h = -16t^2 + v_0t + 921 \). Each term has a specific meaning: the \( -16t^2 \) component represents the downward acceleration due to gravity, pulling the projectile back to the earth as time increases. The \( v_0t \) term represents the initial upward motion imparted by the launch velocity, and finally, \( 921 \) is the initial height from which the launch begins, the top of the Stratosphere Tower. This equation is critical for computing the height of the rider at any moment and can be used to verify times at certain heights, such as when the ride reaches its topmost point, or returns to its starting point.

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Most popular questions from this chapter

REASONING A truck that is 11 feet tall and 7 feet wide is traveling under an arch. The arch can be modeled by \(y=-0.0625 x^2+1.25 x+5.75\), where \(x\) and \(y\) are measured in feet. a. Will the truck fit under the arch? Explain. b. What is the maximum width that a truck 11 feet tall can have and still make it under the arch? c. What is the maximum height that a truck 7 feet wide can have and still make it under the arch?

Determine whether each statement is true or false. If it is true, give an example. If it is false, give a counterexample. a. The sum of two imaginary numbers is an imaginary number. b. The product of two pure imaginary numbers is a real number. c. A pure imaginary number is an imaginary number. d. A complex number is a real number.

Determine whether you would use factoring, square roots, or completing the square to solve the equation. Explain your reasoning. Then solve the equation. \((x+4)^2=16\)

At Buckingham Fountain in Chicago, the height \(h\) (in feet) of the water above the main nozzle can be modeled by \(h=-16 t^2+89.6 t\), where \(t\) is the time (in seconds) since the water has left the nozzle. Describe three different ways you could find the maximum height the water reaches. Then choose a method and find the maximum height of the water.

While marching, a drum major tosses a baton into the air and catches it. The height \(h\) (in feet) of the baton \(t\) seconds after it is thrown can be modeled by the function \(h=-16 t^2+32 t+6\). (See Example 6.) a. Find the maximum height of the baton. b. The drum major catches the baton when it is 4 feet above the ground. How long is the baton in the air?

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