31. An object starts moving from point A and continues along a straight path from A to point D.

Question

If the object starts moving from point A and continues along a straight path from point A to point D, which of the following is true?

a
In the interval from point C to point D, the object travels 0 m.
b
In the interval from point A to point D, the object travels 11 m.
c
In the interval from point B to point C, the object travels 30 m.
d
In the interval from point A to point B, the object travels 30 m.

32. Americium-241 is a radioactive substance used in smoke detectors. The half life of americium is 432 years. If a smoke detector initially contains 1 gram of Americium 241, how much will remain in 1,296 years?

a
0.25 g
b
0.125 g
c
0.5 g
d
1.0 g

33. Match each element to its correct group.
Column A
1. Silver (Ag)
2. Barium (Ba)
3. Iodine (I)
4. Argon (Ar)
5. Potassium (K)

Column B
a. Noble Gas
b. Alkali Metal
c. Alkaline Earth Metal
d. Transition Metal
e. Halogen

34. What is the difference between a vector and a scalar?

a
A vector measurement contains a direction and magnitude, a scalar measurement only contains a magnitude
b
A vector measurement is required for distance, a scalar measurement is required for displacement
c
A vector is only used in measuring forces, a scalar is only used in measuring mass
d
A vector is only measured in SI units, where scalars are only measured in US Customary units

Answer 1

Here are the answers to your questions:

31. The question presents statements about the movement of the object from point A to point D. Without specific details about distances between points A, B, C, and D, it's hard to determine which statement is accurate based on the given information. However, typically:

• a. It states that from C to D, the object travels 0 m, which could only be true if C and D are the same point.
• b. This implies the total distance from A to D is 11 m, which may or may not be factual based on unspecified distances.
• c. This assumes a travel of 30 m from B to C, which also depends on the specifics of the path.
• d. Indicates a distance of 30 m from A to B required to support or contradict subsequent answers.

Assuming the total distance solving supports the correctness of B (which is reasonable), we select b. In the interval from point A to point D, the object travels 11 m.

32. Americium-241 has a half-life of 432 years. To calculate how much remains after 1,296 years:

• 1,296 years corresponds to 3 half-lives (1,296 / 432 = 3).
• After each half-life, the amount is halved:
  • After 1 half-life: 1 g / 2 = 0.5 g
  • After 2 half-lives: 0.5 g / 2 = 0.25 g
  • After 3 half-lives: 0.25 g / 2 = 0.125 g

Thus, the answer is b. 0.125 g.

33. Matching each element to the correct group:

• 1. Silver (Ag) -> d. Transition Metal
• 2. Barium (Ba) -> c. Alkaline Earth Metal
• 3. Iodine (I) -> e. Halogen
• 4. Argon (Ar) -> a. Noble Gas
• 5. Potassium (K) -> b. Alkali Metal

So the matched pairs are:

• 1 -> d
• 2 -> c
• 3 -> e
• 4 -> a
• 5 -> b

34. The difference between a vector and a scalar is:

• a. A vector measurement contains a direction and magnitude, a scalar measurement only contains a magnitude.

So, the correct answer is a.

If you need further clarification or additional questions, feel free to ask!