OAR Mechanical Comprehension: Simple Machines Questions and Answers — Questions and Answers
Question 1: A wheelbarrow is being used to move a heavy load of bricks. This is a classic example of which class of lever?
- A compound lever
- A Class 1 lever
- A Class 2 lever (Correct answer)
- A Class 3 lever
Correct answer: A Class 2 lever
A wheelbarrow is a Class 2 lever because the load (bricks) is located between the fulcrum (the wheel's axle) and the point where the effort is applied (the handles).
Question 2: A block and tackle pulley system is used to lift an engine. If there are 4 rope segments directly supporting the engine, what is the ideal mechanical advantage (IMA) of the system?
- 2
- 8
- 6
- 4 (Correct answer)
Correct answer: 4
The ideal mechanical advantage (IMA) of a pulley system is equal to the number of rope segments that are supporting the load. In this case, with 4 supporting rope segments, the IMA is 4.
Question 3: Which of the following best describes the primary advantage of using an inclined plane to move a heavy object to a higher elevation?
- It decreases the total amount of work required to lift the object.
- It decreases the force required by increasing the distance over which the force is applied. (Correct answer)
- It increases the force required but decreases the distance the object must travel.
- It completely eliminates the force of friction acting on the object.
Correct answer: It decreases the force required by increasing the distance over which the force is applied.
An inclined plane provides a mechanical advantage by allowing the user to apply less force over a longer distance to achieve the same amount of work (lifting the object to a certain height). The total work done remains the same, ignoring friction.
Question 4: An axe head is used to split a log. The axe head functions as which type of simple machine?
- A wedge (Correct answer)
- A screw
- A lever
- A wheel and axle
Correct answer: A wedge
An axe head is a prime example of a wedge. A wedge is a simple machine that consists of two inclined planes placed back-to-back. It works by converting a downward force into two sideways forces, effectively splitting the material apart.
Question 5: When using a screwdriver to tighten a screw, the handle of the screwdriver functions as which part of a simple machine?
- The axle
- The lever arm
- The wheel (Correct answer)
- The fulcrum
Correct answer: The wheel
A screwdriver is an application of the wheel and axle simple machine. The handle is the 'wheel' where a turning force is applied over a larger radius, and the shaft is the 'axle' which transmits this force to the screw. This provides a mechanical advantage, making it easier to turn the screw.
Question 6: Which of the following simple machines is fundamentally an inclined plane wrapped around a cylinder?
- Pulley
- Lever
- Wedge
- Screw (Correct answer)
Correct answer: Screw
A screw is defined as an inclined plane wrapped helically around a central axis or cylinder. The threads of the screw act as the inclined plane, converting rotational force (torque) into a linear force along the screw's axis.
OAR Mechanical Comprehension: Simple Machines Questions and Answers
A wheelbarrow is being used to move a heavy load of bricks.
This is a classic example of which class of lever?