Free DAA Mechanical Comprehension: Levers and Pulleys Questions and Answers — Questions and Answers
Question 1: A seesaw is a classic example of which class of lever?
- Class 1 Lever (Correct answer)
- Class 2 Lever
- Class 3 Lever
- Compound Lever
Correct answer: Class 1 Lever
A Class 1 lever has the fulcrum (pivot point) positioned between the effort and the load. On a seesaw, the pivot is in the middle, with the effort (person pushing down) on one side and the load (person on the other side) on the other.
Question 2: What is the ideal mechanical advantage (IMA) of a single fixed pulley?
- 0
- 1 (Correct answer)
- 2
- It depends on the load
Correct answer: 1
A single fixed pulley does not multiply the force applied; it only changes the direction of the force. Therefore, the effort required to lift the load is equal to the weight of the load, giving it a mechanical advantage of 1.
Question 3: A wheelbarrow is an example of which class of lever?
- Class 1 Lever
- Class 2 Lever (Correct answer)
- Class 3 Lever
- It is not a lever
Correct answer: Class 2 Lever
A Class 2 lever has the load positioned between the fulcrum and the effort. In a wheelbarrow, the wheel's axle is the fulcrum, the load is in the basin, and the effort is applied at the handles.
Question 4: In a pulley system, a load of 100N is lifted by an effort of 25N. What is the mechanical advantage of the system?
- 2
- 3
- 4 (Correct answer)
- 5
Correct answer: 4
Mechanical Advantage (MA) is calculated by dividing the Load by the Effort (MA = Load / Effort). In this case, MA = 100N / 25N = 4. This means the pulley system multiplies the applied force by four times.
Question 5: A fishing rod, when casting a line, functions as which class of lever?
- Class 1 Lever
- Class 2 Lever
- Class 3 Lever (Correct answer)
- Not a lever
Correct answer: Class 3 Lever
A Class 3 lever has the effort applied between the fulcrum and the load. When casting a fishing rod, one hand acts as the fulcrum at the end of the rod, the other hand applies the effort in the middle, and the load is the weight of the line and lure at the tip.
Question 6: To lift a 200kg box using a lever, you apply force 4 metres from the fulcrum. The box is 1 metre from the fulcrum. How much effort (force) is required? (Assume g = 10 m/s²)
- 200N
- 400N
- 500N (Correct answer)
- 800N
Correct answer: 500N
First, calculate the load force: 200kg * 10 m/s² = 2000N. The principle of moments states Effort × Effort Arm = Load × Load Arm. So, Effort × 4m = 2000N × 1m. Effort = 2000 / 4 = 500N.
Question 7: What is the ideal mechanical advantage of a pulley system with 3 movable pulleys and 1 fixed pulley, where the rope is attached to the fixed support?
- 3
- 4
- 6 (Correct answer)
- 7
Correct answer: 6
The ideal mechanical advantage (IMA) of a pulley system is typically equal to the number of rope segments directly supporting the load. In a standard block and tackle arrangement, this is equal to the number of pulleys in the system, but more accurately, it's the number of supporting strands. With 3 movable pulleys, there will be 6 supporting strands, giving an IMA of 6.
Free DAA Mechanical Comprehension: Levers and Pulleys Questions and Answers
A seesaw is a classic example of which class of lever?