GWCB002 Question 2
Problem Statement
Thought Experiments and the History of the Law of Falling Bodies
Problem Statement
Person A decided to research the laws of falling objects and their history. Read the following passage and select the most appropriate number from the options that follow for each question.
“The ancient Greek 1 was a great 3 who lived more than 2 years ago. He believed that when objects fall, ‘the heavier 4 falls faster.’ This theory was widely accepted for a long time, but 6, who was active in the 5th century, exposed the contradiction in this theory through a thought experiment.
Suppose a heavy object and a light object are 7 together with a string. If the old theory were correct, the slower-falling 8 would hold the entire system back, so the two connected objects should fall at 9. However, since connecting the two objects increases the total mass by 10 compared to the original heavy object alone, according to the old theory, the connected objects should fall at 11.
Thus, two contradictory conclusions are derived from the same premises. Therefore, we can conclude that the original theory is 12. In reality, if 13 is a 14 space, then all objects are 15.
(1) Select the person who fits 1.
1: Isaac Newton 2: Galileo Galilei 3: Aristotle 4: Archimedes
(2) Select the most appropriate number of years, counting backward from the present year of 2026, that corresponds to 2.
1: 500 2: 1100 3: 1700 4: 2300
(3) Select his primary title at that time to fill in 3.
1: Physicist 2: Philosopher 3: Astronomer 4: Alchemist
(4) Select the term that fits in 4.
1: Heavy 2: Light 3: Large in volume
(5) Select the century in which Galileo was active that fits in 5.
1: 4 2: 12 3: 16 4: 20
(6) Select the person that fits in 6.
1: Isaac Newton 2: Galileo Galilei 3: René Descartes 4: Copernicus
(7) Select the operation that fits in 7.
1: Tied 2: Collided 3: Rubbed together
(8) Select the term that fits in 8.
1: Heavy object 2: Light object 3: The string itself
(9) Select the description of the fall that fits in 9.
1: A speed faster than that of a single heavy object 2: A speed between that of a heavy object and a light object 3: A speed slower than that of a light object alone
(10) Select the phrase that fits in 10.
1: Heavy 2: Light 3: Unchanged
(11) Select the description of the fall that fits in 11.
1: It must fall as slowly as possible 2: It must fall as fast as possible 3: It must come to a stop partway down
(12) Select the term that fits in 12.
1: Completely correct 2: Incorrect 3: It’s hard to say
(13) Select the phenomenon that fits in 13.
1: Air resistance 2: Gravitational force 3: Electrostatic force
(14) Select the phrase that fits in 14.
1: If present (exists) 2: If absent (can be ignored)
(15) Select the law of falling objects that fits in 15.
1: They fall simultaneously regardless of weight 2: They fall sequentially at speeds proportional to their weight 3: They fall at speeds inversely proportional to their volume
Constraints
- Let Ax be the option number corresponding to the answer for each subquestion (x).
- All Ax values are natural numbers (1, 2, 3, or 4) indicating the correct answer for each option.
Input Format
Let Sodd=A1+A3+A5+A7+A9+A11+A13+A15 be the sum of the answers to the odd-numbered subproblems. Let Seven=A2+A4+A6+A8+A10+A12+A14 be the sum of the answers to the even-numbered subproblems. Find the value of the product Sodd×Seven and enter that natural number.
Solution
Explanation
Explanation of Each Subquestion
- (1), (2), (3): The great “philosopher” of ancient Greece (4th century BCE, approximately 2,300 years ago) was Aristotle. At that time, the natural sciences in general were explored as part of philosophy. Therefore, (1) = 3, (2) = 4, and (3) = 2.
- (4): Aristotle proposed the view that “heavier objects fall faster.” Therefore, (4) = 1.
- (5), (6): Galileo Galilei, who was active in the 16th and 17th centuries, established the methods of modern science. Therefore, (5) = 3 and (6) = 2.
- (7)–(12): This is the process of Galileo’s famous thought experiment (refutation by reductio ad absurdum). When a heavy object and a light object are “tied together,” • “The lighter one slows it down, so they fall at an intermediate speed (slower than the heavy one alone)” • “Since they’ve combined to become heavier, they fall faster than the heavy one alone” These mutually contradictory conclusions are derived simultaneously. The fact that a logical contradiction arises proves that the premise—the theory that “heavier objects fall faster”—is itself “wrong.” Therefore, (7) = 1, (8) = 2, (9) = 2, (10) = 1, (11) = 2, and (12) = 2.
- (13)–(15): In everyday life, the cause of differences in falling speed is “air resistance.” If there were “no” air resistance, all objects would “fall simultaneously regardless of their weight.” Therefore, (13) = 1, (14) = 2, (15) = 1.
Calculating the Final Input Values
Group the correct answer numbers for each subquestion and add them together.
Sum of Odd Numbers (Sodd) Sodd=A1+A3+A5+A7+A9+A11+A13+A15 Sodd=3+2+3+1+2+2+1+1=15
Sum of even-numbered terms (Seven) Seven=A2+A4+A6+A8+A10+A12+A14 Seven=4+1+2+2+1+2+2=14
The value we are looking for is the product of these two expressions. Sodd×Seven=15×14=210
The final natural number is 210.