Nokea
How does friction affect motion?
- A. Friction increases speed
- B. Friction decreases speed
- C. Friction has no impact on speed
- D. Friction causes objects to float
Correct Answer: B
Rationale: Friction is a force that opposes motion when two surfaces are in contact. It acts in the opposite direction to the direction of motion, causing objects to slow down or come to a stop. Therefore, friction decreases speed rather than increasing it. Choice A is incorrect as friction does not increase speed but rather hinders it. Choice C is incorrect because friction does have an impact on speed by slowing down objects. Choice D is incorrect as friction's effect is not making objects float but rather causing resistance to motion.
You may also like to solve these questions
What is the molar mass of Ca(NO3)2?
- A. 74.1 g/mol
- B. 132.1 g/mol
- C. 164.1 g/mol
- D. 78.1 g/mol
Correct Answer: B
Rationale: To calculate the molar mass of Ca(NO3)2, we add up the individual atomic masses of its elements: Ca (40.08) + 2N (2 * 14.01) + 6O (6 * 16.00) = 40.08 + 28.02 + 96.00 = 164.1 g/mol. Therefore, the correct answer is 164.1 g/mol (Choice C). Choice A (74.1 g/mol) is incorrect as it does not account for the correct sum of atomic masses. Choice B (132.1 g/mol) is the correct molar mass calculation for Ca(NO3)2. Choice D (78.1 g/mol) is incorrect and does not reflect the accurate molar mass of the compound.
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 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.
Which part of the brain is responsible for balance and coordination?
- A. Cerebellum
- B. Cerebrum
- C. Hypothalamus
- D. Thalamus
Correct Answer: A
Rationale: The correct answer is the cerebellum. It plays a vital role in balance and coordination by controlling motor functions, precision, and timing of movements. The cerebrum is primarily involved in higher brain functions such as thinking and problem-solving. The hypothalamus regulates essential bodily functions like temperature and hunger, while the thalamus serves as a relay station for sensory information, directing it to the appropriate areas of the brain for processing.
What is the primary function of coronary arteries?
- A. Delivering oxygenated blood throughout the body.
- B. Supplying oxygenated blood to the heart muscle itself.
- C. Carrying deoxygenated blood back to the heart.
- D. Regulating blood pressure through vasoconstriction and vasodilation.
Correct Answer: B
Rationale: The primary function of coronary arteries is to supply oxygenated blood to the heart muscle itself. The heart is a muscle that needs a constant supply of oxygen and nutrients to function properly. Coronary arteries branch off the aorta and specifically deliver oxygenated blood to the heart muscle, ensuring its proper function. Choice A is incorrect because coronary arteries do not deliver blood throughout the entire body but specifically to the heart. Choice C is incorrect as coronary arteries carry oxygenated blood away from the heart. Choice D is incorrect as the primary function of the coronary arteries is not to regulate blood pressure but rather to provide oxygenated blood to the heart muscle.