EIAT and NEIEP Test EIAT Mechanical 3 — Questions and Answers
Question 1: A belt connects a 4-inch drive pulley spinning at 1,200 RPM to a 12-inch driven pulley. What is the speed of the driven pulley?
- 3,600 RPM
- 400 RPM (Correct answer)
- 900 RPM
- 300 RPM
Correct answer: 400 RPM
Speed ratio = drive diameter / driven diameter = 4/12 = 1/3, so 1,200 × (4/12) = 400 RPM.
Question 2: A spring with a spring constant of 20 lb/in is compressed 3 inches. How much force is required to hold it in the compressed position?
- 6.67 lb
- 23 lb
- 60 lb (Correct answer)
- 17 lb
Correct answer: 60 lb
Hooke's Law: F = k × x = 20 lb/in × 3 in = 60 lb.
Question 3: Which class of lever has the effort between the fulcrum and the load?
- First class
- Second class
- Third class (Correct answer)
- Fourth class
Correct answer: Third class
A third-class lever has the effort between the fulcrum and load, providing a mechanical advantage less than 1 but greater speed and range of motion.
Question 4: A pipe with a 4-inch diameter is connected to a pipe with a 2-inch diameter. If water flows at 2 ft/s in the large pipe, how fast does it flow in the small pipe?
- 4 ft/s
- 8 ft/s (Correct answer)
- 1 ft/s
- 16 ft/s
Correct answer: 8 ft/s
Continuity equation: A1×v1 = A2×v2; area ratio is (4²)/(2²) = 4, so v2 = 2 × 4 = 8 ft/s.
Question 5: What is the primary function of a flywheel in a mechanical system?
- To increase gear ratios
- To store rotational kinetic energy and smooth out speed variations (Correct answer)
- To change the direction of rotation
- To increase friction in the drivetrain
Correct answer: To store rotational kinetic energy and smooth out speed variations
A flywheel stores rotational energy and releases it to maintain constant speed during load variations.
Question 6: When a bolt is tightened, the threads act as which simple machine?
- Lever
- Pulley
- Screw (inclined plane wrapped around a cylinder) (Correct answer)
- Wedge
Correct answer: Screw (inclined plane wrapped around a cylinder)
A screw is an inclined plane wrapped around a cylinder; rotating it converts rotational motion into linear clamping force.
Question 7: A first-class lever has a 200 lb load 2 feet from the fulcrum. Where must a 50 lb effort be applied to achieve balance?
- 2 feet from the fulcrum on the same side
- 8 feet from the fulcrum on the opposite side (Correct answer)
- 4 feet from the fulcrum on the opposite side
- 1 foot from the fulcrum on the opposite side
Correct answer: 8 feet from the fulcrum on the opposite side
Torque balance: 200 lb × 2 ft = 50 lb × d, so d = 400/50 = 8 feet.
EIAT and NEIEP Test EIAT Mechanical 3
A belt connects a 4-inch drive pulley spinning at 1,200 RPM to a 12-inch driven pulley.
What is the speed of the driven pulley?