CPS Mechanical Aptitude Principles 3 — Questions and Answers
Question 1: A 100-lb load rests on a board pivoting on a fulcrum. The load is 2 ft from the fulcrum and the effort arm is 8 ft. How much effort is needed to balance it?
- 25 lb (Correct answer)
- 50 lb
- 100 lb
- 400 lb
Correct answer: 25 lb
Effort × effort arm = load × load arm: 100 × 2 = E × 8, so E = 25 lb.
Question 2: A block-and-tackle system has 4 supporting rope sections lifting a load. What is its ideal mechanical advantage?
- 4 (Correct answer)
- 2
- 8
- 1
Correct answer: 4
Mechanical advantage of a pulley system equals the number of rope sections supporting the load.
Question 3: A longer ramp used to raise a barrel to the same height requires what change in pushing force?
- Less force over a longer distance (Correct answer)
- More force over a shorter distance
- The same force as a vertical lift
- No force at all
Correct answer: Less force over a longer distance
A longer inclined plane reduces the force needed but increases the distance traveled.
Question 4: Which of these is an example of a third-class lever?
- A pair of tweezers (Correct answer)
- A seesaw
- A wheelbarrow
- A nail puller
Correct answer: A pair of tweezers
Tweezers apply effort between the fulcrum and load, defining a third-class lever.
Question 5: Two gears mesh, and an idler gear is placed between the driver and driven gears. What is the idler gear's main effect?
- It reverses the driven gear's direction without changing the speed ratio (Correct answer)
- It doubles the output speed
- It halves the output torque
- It locks the system
Correct answer: It reverses the driven gear's direction without changing the speed ratio
An idler gear changes rotation direction but does not alter the overall speed ratio between driver and driven.
Question 6: A hydraulic system uses a small piston to push fluid against a large piston. What is the main benefit?
- A small input force creates a large output force (Correct answer)
- Fluid moves faster
- The system uses less fluid
- It generates electricity
Correct answer: A small input force creates a large output force
Hydraulic systems multiply force because pressure acts over a larger output piston area.
Question 7: Which material property describes how well a substance returns to its original shape after being stretched?
- Elasticity (Correct answer)
- Density
- Conductivity
- Viscosity
Correct answer: Elasticity
Elasticity is the ability of a material to return to its original shape after deformation.
CPS Mechanical Aptitude Principles 3
A 100-lb load rests on a board pivoting on a fulcrum.
The load is 2 ft from the fulcrum and the effort arm is 8 ft.
How much effort is needed to balance it?