56. Which of the following mechanism changes the constant speed rotary motion into
intermittent reciprocating linear motion?
(A)Chain drive (B)Cam mechanism (C)Simple gear train (D)Worm and wheel
79. If your extension power cord at home is short-circuited, which device will most likely
respond for safety?
(A)Voltage panel (B)Protection gauge
(C)Circuit breaker (D)Electrical insulation