Tv broadcast antennas are the tallest artificial structures on earth. in 1987, a 79.0 kg physicist placed himself and 400 kg of equipment at the top of one 610 m high antenna to perform gravity experiments. by how much (in mm) was the antenna compressed, if we consider it to be equivalent to a steel cylinder 0.125 m in radius? (assume a young's modulus of 20 ⨯ 1010 pa.)

m

Explanation:

= mass of physicist and his equipment together = 79 + 400 = 479 kg

Force applied by weight of physicist and his equipment together on the antenna is given as

N

= original length of the antenna = 610 m

= compression in the length of the antenna

= radius of the cylinder = 0.125 m

Area of cross-section of the cylinder is given as

m²

= Young's modulus of steel = 20 x 10¹⁰ Pa

Young's modulus is given as

Inserting the above values

m

the device is called “ rocket engine”

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explanation: