(a) The brake used in modern elevators (b) Jet Engine (c) Turbine (d) Hydraulic Crane
Answer : (a)
Explanation : In 1853, American inventor Elisha Otis demonstrated a freight elevator equipped with a safety device to prevent falling in case a supporting cable should break. This increased public confidence in such devices. Otis established a company for manufacturing elevators and patented (1861) a steam elevator. Many people think that he invented the elevator, but the truth is, he invented the elevator brake. He also invented the railway safety brake.
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