# TV broadcast antennas are the tallest artificial structures on Earth. In 1987, a 65.0 kg...

## Question:

{eq}TV {/eq} broadcast antennas are the tallest artificial structures on Earth. In {eq}1987 {/eq}, a {eq}65.0 \ kg {/eq} physicist placed himself and {eq}400 \ kg {/eq} of equipment at the top of one {eq}610 \ m {/eq} high antenna to perform gravity experiments. By how much (in {eq}mm {/eq}) was the antenna compressed, if we consider it to be equivalent to a steel cylinder {eq}0.160 \ m {/eq} in radius?

## Hooke's law

The weight of physicist and equipments (W) gives a downward force on the antenna, which is balanced by normal reaction force (N') from the ground on the antenna. So, weight force W and normal force N' are responsible for compressing the antenna.

## Answer and Explanation: 1

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Total weight on top of antenna W = (65+400)*9.8 N = 4557 N

Cross section area of antenna {eq}A = \pi r^2 = 3.14* 0.16*0.16 = 0.080384\ m^2 {/eq}

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#### Learn more about this topic: Shear and Bulk Stress and Strain Equations

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Chapter 8 / Lesson 6
4.4K

Discover how to tell when an object is experiencing normal, shear, and bulk stress and strain in this lesson. Then, learn about the basic formulas we use to find shear and bulk stresses, strains, and moduli.