PhysicsClassical Physics
State the Second Law of Motion: Meaning, Formula, and Conditions
Newton’s second law relates net external force to momentum change and reduces to net force equals mass times acceleration when the system mass is constant.
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PhysicsClassical Physics
If Velocity Is Constant, Then Acceleration Is What?
A constant velocity vector has zero time derivative, so the acceleration is zero; constant speed is different because direction can still change.
PhysicsClassical Physics
An Astronaut Stands on the Surface of a Spherical Asteroid: Escape and Rotation Limits
For an Earth-density spherical asteroid, the astronaut can escape by jumping only if the radius is about 1.8 km or less; the cohesionless rotation limit has an 84.6-minute period.
PhysicsClassical Physics
A 20 kg Box on a Horizontal Frictionless Surface Attached to a Spring
The spring does negative 160 J of work, has k = 1280 N/m, produces a maximum acceleration of 32 m/s², and oscillates at about 1.27 Hz.
BiologyGenetics
An Organism That Has Two Different Alleles for a Trait: Genetics Vocabulary Match
An organism with two different alleles at a locus is heterozygous. The full matching key also separates genotype, phenotype, homozygous, codominance, probability, and Punnett square.
ChemistryOrganic Chemistry
A Basic Amino Acid Has an R Group That Contains What?
A basic amino acid has a protonatable nitrogen-containing side chain. Lysine uses an amine, arginine a guanidinium group, and histidine an imidazole ring.
BiologyCell Biology
During Which Phase Do Chromosomes First Become Visible?
Chromosomes first become visibly distinct during prophase as chromatin condenses. They already existed as less compact chromatin before this stage.
BiologyCell Biology
During Which Phase of Mitosis Do Sister Chromatids Separate?
Sister chromatids separate during anaphase. Cohesin release allows them to move to opposite poles, after which each is a daughter chromosome.
Anatomy & PhysiologyHistology
Which of the Following Is Not a Feature of Epithelia? Answer and Explanation
Abundant extracellular matrix is not a feature of epithelia. Epithelial tissue is highly cellular, polarized, and nearly avascular.