Mechanical Aptitude Mechanical Aptitude Hydraulics and Pneumatics 2 — Questions and Answers
Question 1: In a hydraulic system, if the input piston has an area of 2 sq in and the output piston has an area of 10 sq in, what is the mechanical advantage?
- 2
- 5 (Correct answer)
- 10
- 20
Correct answer: 5
Mechanical advantage equals output area divided by input area: 10 ÷ 2 = 5.
Question 2: What type of valve controls the rate of fluid flow in a hydraulic circuit?
- Check valve
- Relief valve
- Flow control valve (Correct answer)
- Directional control valve
Correct answer: Flow control valve
A flow control valve regulates the speed of actuators by restricting or allowing fluid flow rate.
Question 3: Which component in a pneumatic system removes moisture from compressed air?
- Lubricator
- Air dryer (Correct answer)
- Regulator
- Muffler
Correct answer: Air dryer
An air dryer (or filter/dryer) removes water vapor from compressed air to prevent corrosion and damage.
Question 4: What happens to fluid pressure when it passes through a restriction (orifice) in a hydraulic line?
- Pressure increases
- Pressure decreases (Correct answer)
- Pressure stays the same
- Pressure reverses
Correct answer: Pressure decreases
According to Bernoulli's principle, fluid pressure drops as it passes through a restriction due to increased velocity.
Question 5: A double-acting hydraulic cylinder differs from a single-acting cylinder because it:
- Uses two fluids simultaneously
- Can be powered in both extend and retract directions (Correct answer)
- Has twice the pressure rating
- Requires two pumps to operate
Correct answer: Can be powered in both extend and retract directions
A double-acting cylinder uses hydraulic pressure to both extend and retract the rod, while a single-acting cylinder relies on a spring or gravity for one direction.
Question 6: In pneumatics, what is the primary purpose of a lubricator in an FRL unit?
- Filter particulates from air
- Reduce air pressure to safe levels
- Add oil mist to protect moving parts (Correct answer)
- Silence exhaust air noise
Correct answer: Add oil mist to protect moving parts
The lubricator adds a fine oil mist to compressed air to lubricate internal components of pneumatic tools and cylinders.
Question 7: Which law states that pressure applied to a confined fluid is transmitted equally in all directions?
- Boyle's Law
- Newton's Third Law
- Pascal's Law (Correct answer)
- Bernoulli's Principle
Correct answer: Pascal's Law
Pascal's Law states that pressure applied to an enclosed fluid is transmitted undiminished in all directions throughout the fluid.
Mechanical Aptitude Mechanical Aptitude Hydraulics and Pneumatics 2
In a hydraulic system, if the input piston has an area of 2 sq in and the output piston has an area of 10 sq in, what is the mechanical advantage?