46.

What Thomas Davenport invented?
A. Screw propellor B. Electric streetcar
C. Chesterfield D. Sleeping (railway) car
Answer and Explanation
Answer:B
Explanation: Invented in 1834.
47.

What Elisha Otis invented?
A. The brake used in modern elevators B. Jet Engine
C. Turbine D. Hydraulic Crane
Answer and Explanation
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.
48.

Where was the yo-yo invented?
A. France B. United States
C. Philippines D. England
Answer and Explanation
Answer:C
Explanation: The yo-yo was first used by hunters as weapons. They were wooden disks on strings. In the 1920s, a man from the U.S. named Donald Duncan made the yo-yo into a toy after he visited the Philippines.
49.

For what does the world owe Almon Strowger a debt of gratitude?
A. Parking Meters B. Vending Machines
C. Automatic Telephone Exchanges D. Traffic Lights
Answer and Explanation
Answer:C
Explanation: He was an undertaker, and legend has it, he developed the automatic switch in 1889, to stop competitors from getting his work!
50.

Who is often called the 'first African-American' inventor?
A. Bessie Blount B. George Washington Carver
C. Benjamin Banneker D. Elijah McCoy
Answer and Explanation
Answer:C
Explanation: Banneker was a member of the planning committee that designed Washington, DC along with Pierre L'Enfant. When L'Enfant was fired Banneker recreated the plans from memory.