What is the momentum of a car with a mass of 1500 kg moving at a speed of 20 m/s?

Correct Answer: A

Rationale: The momentum of an object is calculated by multiplying its mass by its velocity. In this case, the momentum of the car can be determined using the formula momentum = mass x velocity. Substituting the given values, momentum = 1500 kg x 20 m/s = 30,000 kg m/s. Therefore, the correct answer is A, 30,000 kg m/s. Choice B (1500 kg m/s) is incorrect because that value represents the mass of the car, not its momentum. Choice C (20 kg m/s) is incorrect as it only represents the speed of the car, not its momentum. Choice D (Momentum cannot be determined without knowing the direction of motion) is incorrect because momentum is a vector quantity and can be determined using magnitude and direction, but in this case, only the magnitude is required.

Correct Answer: C

Rationale: Nuclear fusion releases a large amount of energy in a short time by combining two light atomic nuclei to form a heavier nucleus. This process is the energy source of the sun and hydrogen bombs. Radioactivity involves the spontaneous emission of particles or energy from an unstable atomic nucleus, while nuclear fission is the splitting of a heavy atomic nucleus into two or more lighter nuclei, also releasing energy. While all the options are types of nuclear reactions, nuclear fusion is specifically known for releasing a large amount of energy rapidly, making it the correct choice in this context. Choices A and B are incorrect as they do not specifically describe the process of releasing a large amount of energy in a short time. Choice D is incorrect because not all the options listed release a large amount of energy in a short time, making it an inaccurate answer.

Correct Answer: B

Rationale: The correct answer is B. The two main types of nuclear decay are alpha and beta decay, which are differentiated based on the emitted particle. In alpha decay, an alpha particle (consisting of two protons and two neutrons) is emitted from the nucleus, while in beta decay, a beta particle (either an electron or a positron) is emitted. These decay types are distinguished by the particles they emit, not by the size of the nucleus, trigger, or stability of the nucleus. Choices A, C, and D are incorrect because fission, fusion, spontaneous, induced, isotope decay, and chain reactions are different processes in nuclear physics and do not represent the two main types of nuclear decay based on emitted particles.

Correct Answer: D

Rationale: CRISPR-Cas9 is the correct answer. A) Polymerase Chain Reaction (PCR) is used for amplifying specific DNA segments, not directly editing the human genome. B) Gel electrophoresis is for separating DNA fragments by size, not for genome editing. C) DNA sequencing determines DNA nucleotide order but does not directly edit the genome. D) CRISPR-Cas9 technology enables precise modifications in the DNA of organisms, including humans. It guides the Cas9 enzyme to specific genome locations for targeted edits, revolutionizing genetic research and offering various applications in gene editing and therapy. Unlike the other techniques mentioned, CRISPR-Cas9 is specifically designed to make changes in the genetic code itself, making it a powerful tool for genetic manipulation.

Correct Answer: B

Rationale: Rationale: - Germline mutations are changes in the DNA of reproductive cells (sperm or egg cells) and can be passed on to offspring, affecting all cells in the resulting organism. - Somatic mutations are changes in the DNA of non-reproductive cells (body cells) and are not passed on to offspring. These mutations only affect the cells that arise from the mutated cell. - Option A is incorrect because somatic mutations are not passed to offspring. - Option C is incorrect because both germline and somatic mutations can affect any DNA. - Option D is incorrect because the effects of mutations, whether germline or somatic, can be beneficial, harmful, or have no significant impact.