HESI A2 Physics

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 momentum of an object is calculated by multiplying its mass by its velocity. In this case, the glider has the greatest momentum because it has the highest product of mass and velocity compared to the other choices. The glider's momentum is calculated as 500 kg * 89 m/s = 44500 kg*m/s, which is higher than the momentum of any other vehicle listed. The other choices have lower momentum values due to either lower mass, lower velocity, or both. So, the correct answer is D because it has the greatest momentum based on its mass and velocity.

Correct Answer: D

Rationale: To calculate work, we use the formula W = F*d, where W is work, F is force, and d is distance. In this case, the force is 15 N and the distance is 3 m. So, W = 15 N * 3 m = 45 N⋅m. Therefore, the correct answer is D. Choice A is incorrect as it incorrectly calculates work by dividing force by distance. Choice B is incorrect as it only provides the correct unit for work, not the actual calculation. Choice C is incorrect as it incorrectly multiplies force and distance to get the wrong result.

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: B

Rationale: The correct answer is B: Newton's second law of motion. This law states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. The formula for this relationship is F = ma, where F is the force applied, m is the mass of the object, and a is the acceleration produced. This equation clearly expresses the relationship between acceleration and force. Now, let's analyze why the other choices are incorrect: A: Newton's first law of motion, also known as the law of inertia, states that an object at rest will remain at rest, and an object in motion will remain in motion unless acted upon by an external force. This law does not directly relate to the relationship between acceleration and force. C: Newton's third law of motion states that for every action, there is an equal and opposite reaction. This law describes the interaction between two objects and their forces, not the relationship between acceleration and force. D: Saying