Free NYS Civil Service PCO Test Questions and Answers — Questions and Answers
Question 1: Alters the direction of the load's effort. Instead of pulling downward, you do so upward. It has a single wheel and a rope. The weight of the load determines how much force is necessary to lift it.
- TRUE
- FALSE (Correct answer)
Correct answer: FALSE
This description accurately details a fixed pulley, which changes the direction of the applied force but does not reduce the magnitude of force required to lift the load. The force needed to lift the load using a fixed pulley is equal to the load's weight (ignoring friction). Therefore, if the statement implies a reduction in the force necessary, it is false, as a fixed pulley only offers a mechanical advantage in direction, not force magnitude.
Question 2: Have sloping faces and toothed wheels that mesh at a specific angle.
- Worm gears
- Spur gears
- Bevel gears (Correct answer)
- Helical gears
Correct answer: Bevel gears
Bevel gears are distinct for their conical shape and teeth cut on sloping faces. This design allows them to transmit power efficiently between shafts that intersect at an angle, typically 90 degrees. Their unique geometry makes them suitable for applications requiring power transfer between non-parallel, intersecting axes, unlike spur or helical gears which are for parallel shafts.
Question 3: Machines with few moving parts
- Inclined plane
- Fixed pulley
- Simple pulley
- Simple machines (Correct answer)
Correct answer: Simple machines
Simple machines are fundamental mechanical devices designed to change the direction or magnitude of a force. They are characterized by having few or no moving parts, serving as the basic building blocks for more complex machinery. Examples include levers, pulleys, inclined planes, wedges, screws, and wheels and axles.
Question 4: A wheel with teeth along its edge that engage with other gear wheels or other teeth to provide movement
- Lever
- Inclined Wheel
- Gearwheel (Correct answer)
- Fulcrum Wheel
Correct answer: Gearwheel
A gearwheel, commonly known as a gear, is a rotating machine part specifically designed with cut teeth along its edge. These teeth mesh with those of another toothed part to transmit torque, change speed, or alter the direction of movement. This definition precisely describes its function and structure within mechanical systems.
Question 5: A straightforward device that uses a stiff bar that pivots on a supporting piece to lift or pry up a weight at one end by applying force at the other
- Lever (Correct answer)
- Pulley
- Load
- Block And Tackle
Correct answer: Lever
This description accurately defines a lever, which is a simple machine consisting of a rigid bar that pivots around a fixed point called a fulcrum. By applying force at one end, a lever can multiply that force to lift or move a load at the other end. Common examples include crowbars and seesaws.
Question 6: It has two lever arms attached at a pivot, similar to scissors or pliers.
- Inclined plane
- Pair of levers (Correct answer)
- Lever
- Fulcrum/pivot
Correct answer: Pair of levers
Scissors and pliers are classic examples of compound machines that function as a 'pair of levers.' Each blade or jaw acts as an individual lever arm, and they are joined at a common pivot point, or fulcrum. This arrangement allows for the effective application of force to cut, grip, or manipulate objects.
Question 7: When using a compressed air sprayer to treat cracks and crevices, the recommended internal pressure is
- 165 to 185 degrees Fahrenheit
- 30 to 35 psi
- 5 to 20 psi (Correct answer)
- 30 to 75 psi
Correct answer: 5 to 20 psi
When using a compressed air sprayer to treat cracks and crevices, a low internal pressure of 5 to 20 psi is recommended. This lower pressure ensures precise application of the pesticide, minimizing drift and overspray onto non-target areas. Higher pressures would create a fine mist that is harder to control and more prone to unintended dispersal.
Free NYS Civil Service PCO Test Questions and Answers
Alters the direction of the load's effort.
Instead of pulling downward, you do so upward.
It has a single wheel and a rope.
The weight of the load determines how much force is necessary to lift it.