/*! 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 22 An aerialist on a high platform ... [FREE SOLUTION] | 91Ó°ÊÓ

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An aerialist on a high platform holds on to a trapeze attached to a support by an \(8.0-\mathrm{m}\) cord. (See the drawing.) Just before he jumps off the platform, the cord makes an angle of 41 \(^{\circ}\) with the vertical. He jumps, swings down, then back up, releasing the trapeze at the instant it is \(0.75 \mathrm{m}\) below its initial height. Calculate the angle \(\theta\) that the trapeze cord makes with the vertical at this instant.

Short Answer

Expert verified
\( \theta \approx 47.2^{\circ} \).

Step by step solution

01

Understanding the Problem

We need to find the angle \( \theta \) that the trapeze makes with the vertical when the aerialist is 0.75 m below the initial height. We know the cord length is 8.0 m and the initial angle with the vertical is 41°.
02

Determine the Total Drop

The aerialist starts at a height with the trapeze cord making a 41° angle with the vertical. The total vertical drop when he releases the trapeze is 0.75 m. We need to determine the height of the trapeze above the lowest point of the swing.
03

Calculate Initial Height Drop

Using trigonometry, the height \( h_1 \) from which the aerialist starts to drop can be calculated as \( h_1 = 8.0 \cos(41°) \).
04

Calculate Final Height Drop

The final height \( h_2 \) just before he lets go can be calculated as \( h_2 = h_1 - 0.75 \).
05

Using Cosine to Find Final Angle

The height at which he releases the trapeze is \( h_2 = 8.0 \cos(\theta) \). By setting this equal to the calculated final height \( h_2 \), we find \( \cos(\theta) = \frac{h_2}{8.0} \).
06

Solving for \( \theta \)

Compute \( \theta \) by using the inverse cosine function: \( \theta = \cos^{-1}\left( \frac{h_2}{8.0} \right) \).
07

Plug in Values and Simplify

First calculate \( h_2 = 8.0\cos(41°) - 0.75 \). Then compute \( \theta \) as \( \theta = \cos^{-1}\left( \frac{h_2}{8.0} \right) \) using the calculated \( h_2 \).

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Key Concepts

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

Physics Problem Solving
When tackling any physics problem, it's important to establish a clear understanding of what is known and what you need to find out. The problem we are addressing involves a trapeze artist and consists of understanding how the trapeze moves when the artist swings and releases it.

First, define all the known values from the problem. In our case, the length of the trapeze cord is 8.0 meters, and the initial angle with the vertical is 41 degrees. You will also need to determine the angle when the swing is 0.75 meters lower than its initial height.

Next, break the problem into manageable steps. A large problem can often be simplified into smaller parts, which allows for an easier application of physical laws and concepts. Here, understanding the changes in height and how they relate to the angle is crucial.

Always re-evaluate your step-by-step method. Physics involves continual analysis and adjustment. Confirm that each calculation makes sense physically; check that angles and distances are logically consistent with how they should behave.
Trapeze Motion
Trapeze motion in this problem can be thought of as pendulum-like motion. The trapeze artist swings from a higher point down to a lower point and then back up again. Central concepts of this type of motion include potential energy, kinetic energy, and the conservation of mechanical energy.

Initially, the trapeze is at rest at some height. The primary force acting on the aerialist is gravity. As the trapeze swings downward, potential energy converts into kinetic energy, causing the artist to swing faster. At the lowest point of the swing, the potential energy is at a minimum, and the kinetic energy is at a maximum. This energy transformation governs the motion across the swing.

Understanding the height change is key here. The trapeze artist's vertical position changes, which affects the angle of the cord with the vertical. By knowing the vertical drop of 0.75 meters, you can compute how this affects the potential energy and thus the swing's endpoint position.
Inverse Cosine Function
The inverse cosine function, also known as arccosine, is key to determining angles when given the cosine value. In this problem, once we have the final height calculation, we can decide how the vertical angle has changed by using the inverse cosine function.

The cosine of an angle in a right triangle is the ratio of the adjacent side to the hypotenuse. So, \[ \cos(\theta) = \frac{\text{adjacent}}{\text{hypotenuse}} \]
In our problem, the "adjacent" side in the angle calculation is the new height the trapeze reaches, and the "hypotenuse" is the length of the trapeze cord, which remains constant at 8 meters.

The inverse cosine function allows you to go backward—finding the angle when you know the ratio. After computing the height the trapeze artist reached using the cosine of the initial angle, we use: \[ \theta = \cos^{-1}\left( \frac{h_2}{8.0} \right) \]
Plug in the known \( h_2 \) value to calculate the angle \( \theta \), thus completing the understanding of how the angle has changed during the trapeze motion.

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