Nokea
What determines the final velocity of a block sliding down a frictionless inclined plane?
- A. The length of the incline
- B. The angle of the incline
- C. The mass of the block
- D. All of the above
Correct Answer: B
Rationale: The final velocity of a block sliding down a frictionless inclined plane is determined by the angle of the incline. The angle directly impacts the acceleration of the block, affecting the final velocity it attains at the bottom. The length of the incline and the mass of the block do not play a direct role in determining the final velocity. Therefore, the correct answer is the angle of the incline (Choice B). Choices A and C are incorrect because the length of the incline and the mass of the block do not have a direct influence on the final velocity of the block in this scenario.
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Which type of muscle is found in the walls of hollow organs, such as the stomach and intestines, and is responsible for involuntary contractions to propel substances through the organs?
- A. Cardiac muscle
- B. Smooth muscle
- C. Skeletal muscle
- D. Striated muscle
Correct Answer: B
Rationale: Smooth muscle is the correct answer. It is found in the walls of hollow organs like the stomach and intestines, where it performs involuntary contractions to move substances through these organs. Cardiac muscle, found in the heart, is responsible for pumping blood. Skeletal muscle is attached to bones and involved in voluntary movements. Striated muscle is a term often used interchangeably with skeletal muscle, which is responsible for voluntary movements but not typically found in the walls of hollow organs like the stomach and intestines.
A guitar string vibrates at a fundamental frequency of 440 Hz. What is the frequency of the second harmonic (first overtone)?
- A. 220 Hz
- B. 440 Hz
- C. 880 Hz
- D. 1760 Hz
Correct Answer: C
Rationale: The second harmonic (first overtone) is twice the frequency of the fundamental frequency. Therefore, the frequency of the second harmonic is 440 Hz * 2 = 880 Hz. The second harmonic has a frequency that is one octave higher than the fundamental frequency, representing the first overtone of the vibrating string. Choice A (220 Hz) is incorrect as it represents half the fundamental frequency and is the second harmonic, not the first overtone. Choice B (440 Hz) is the fundamental frequency itself. Choice D (1760 Hz) is the frequency of the fourth harmonic, not the second harmonic.
What happens to the density of a substance if its mass increases while its volume remains constant?
- A. Density increases
- B. Density decreases
- C. Density remains constant
- D. Density becomes zero
Correct Answer: A
Rationale: When the mass of a substance increases while its volume remains constant, the density, which is calculated by dividing mass by volume, will increase. This is because with a higher mass and the volume staying the same, the ratio of mass to volume (density) will be greater, resulting in an overall increase in density. Choice B, 'Density decreases,' is incorrect because an increase in mass with constant volume leads to a higher density. Choice C, 'Density remains constant,' is incorrect as an increase in mass will cause the density to increase. Choice D, 'Density becomes zero,' is incorrect because even with an increase in mass, as long as volume remains constant, density will not reach zero; it will increase instead.
What is the term for the energy absorbed during a chemical reaction?
- A. Kinetic energy
- B. Potential energy
- C. Heat energy
- D. Endothermic energy
Correct Answer: D
Rationale: The correct term for the energy absorbed during a chemical reaction is 'Endothermic energy.' Endothermic reactions absorb energy from their surroundings, leading to a decrease in temperature. The prefix 'endo-' means 'inward' or 'within,' indicating that energy is taken in during the reaction. Choices A, B, and C are incorrect because kinetic energy refers to the energy of motion, potential energy is stored energy, and heat energy is a form of energy transfer rather than specifically the energy absorbed during a chemical reaction.
Which kingdom primarily consists of multicellular, photosynthetic organisms with cell walls made of cellulose?
- A. Animalia
- B. Fungi
- C. Plantae
- D. Protista
Correct Answer: C
Rationale: A) Animalia consists of multicellular organisms that lack cell walls and are heterotrophic. Therefore, it does not primarily consist of photosynthetic organisms with cell walls made of cellulose. B) Fungi are multicellular organisms with cell walls made of chitin and are heterotrophic, so they do not fit the description. C) Plantae primarily consists of multicellular, photosynthetic organisms with cell walls made of cellulose. This accurately describes plants. D) Protista is a diverse kingdom that includes unicellular and multicellular organisms with varying characteristics, but it does not primarily consist of multicellular, photosynthetic organisms with cell walls made of cellulose.