Mechanical Comprehension Flashcards
7 cards from real EIAT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Mechanical Comprehension flashcards as text
Work is calculated as:
Answer: Force × distance
Work (W) = Force (F) × Distance (d); it measures the energy transferred when a force moves an object over a distance.
A cam mechanism is used to convert:
Answer: Rotary motion into reciprocating linear motion
A cam converts the continuous rotational motion of a shaft into back-and-forth (reciprocating) linear motion of a follower.
In a traction elevator, rope grip is maintained by:
Answer: Friction between the rope and sheave grooves
Traction drive relies on friction in the grooved sheave — rope tension and groove geometry (undercut or round) generate the tractive force.
What effect does doubling the diameter of a pipe have on its cross-sectional area?
Answer: Quadruples the area
Area = π(d/2)²; doubling d gives π(d)² which is 4 times the original area, so flow capacity increases four-fold.
An elevator cab weighs 3,000 lb and is lifted 40 feet in 20 seconds. The power required (ignoring losses) is approximately:
Answer: 6,000 ft-lb/s (10.9 HP)
Power = Work/Time = (3,000 lb × 40 ft) / 20 s = 6,000 ft-lb/s; dividing by 550 gives ~10.9 HP.
A worm gear drive is considered self-locking when the:
Answer: Lead angle of the worm is less than the friction angle
Self-locking occurs when the worm's lead angle is smaller than the friction angle, preventing back-driving from the gear side.
The purpose of a compensation rope or chain in a high-rise elevator is to:
Answer: Balance the weight of the long hoisting ropes that shifts as the cab travels
As the cab rises, hoisting rope weight shifts to the counterweight side; compensation ropes hanging below the cab and counterweight rebalance this weight difference.