HESI A2 Physics

Correct Answer: D

Rationale: The correct answer is D: Strongly repulsive. When two identical positively charged spheres are brought close together, they will experience a strong repulsive force due to like charges repelling each other based on Coulomb's Law. The force between them is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. The repulsive force will increase as the spheres get closer, leading to a strong repulsion. Choices A and C are incorrect because like charges do not attract each other. Choice B is incorrect as the spheres will experience a repulsive force, not a zero force.

Correct Answer: C

Rationale: The correct answer is C (24 units). When you double the mass of both objects, the gravitational force between them increases by a factor of 4 (2 times 2). Therefore, the new force of attraction would be 12 units x 4 = 24 units. Choice A (3 units) and B (6 units) are incorrect because they do not account for the increase in mass. Choice D (48 units) is incorrect as it overestimates the effect of doubling the mass on the gravitational force.

Correct Answer: D

Rationale: The correct answer is D: Kinetic energy. Potential energy is the energy stored in an object due to its position or state. As the vehicle rolls downhill, potential energy decreases while kinetic energy, the energy of motion, increases. This transformation occurs as the vehicle gains speed and moves due to the force of gravity. The other choices are incorrect because thermal energy is not directly related to the motion of the vehicle in this scenario, and the transformation does not involve a combination of thermal and kinetic energy. The vehicle's movement downhill is primarily a conversion of potential energy into kinetic energy.

Correct Answer: B

Rationale: The correct answer is B: F_b = W_d, the weight of the fluid displaced by the object. This is because the buoyant force acting on an object submerged in a fluid is equal to the weight of the fluid displaced by the object, as stated by Archimedes' principle. When an object is submerged, it displaces a volume of fluid equal to its own volume. The weight of this displaced fluid exerts an upward force on the object, which is the buoyant force. Choices A, C, and D are incorrect because the buoyant force is not equal to the object's weight, the density of the fluid, or the object's volume. The correct answer is based on the principle of fluid displacement and buoyancy.

Correct Answer: D

Rationale: The correct answer is D because salt increases the density of water, making it more buoyant. Higher water density provides greater buoyant force on the boat, allowing it to float more easily. Choices A, B, and C are incorrect as salt does not directly affect the mass of the boat, the volume of water, or the density of the boat itself.