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 impulse, we use the formula Impulse = Change in Momentum. First, calculate the initial momentum: initial momentum = 10 kg * 5 m/s = 50 kg⋅m/s. Then, calculate the final momentum: final momentum = 10 kg * 15 m/s = 150 kg⋅m/s. The change in momentum is final momentum - initial momentum = 150 kg⋅m/s - 50 kg⋅m/s = 100 kg⋅m/s. Therefore, the impulse applied to the object is 100 kg⋅m/s. Choice D is correct as it correctly represents the impulse value. Choices A, B, and C are incorrect as they do not accurately reflect the calculated impulse value.

Correct Answer: C

Rationale: The correct answer is C: Heat. When current flows through a circuit with resistance, the resistance causes collisions between electrons and atoms, resulting in energy loss in the form of heat. This is known as Joule heating. Light (A) is not typically generated by electrical resistance, and sound (B) is not a common form of energy dissipation in circuits. Mechanical work (D) involves movement and is not directly related to energy dissipation due to resistance.

Correct Answer: B

Rationale: The correct answer is B: The bicycle has less kinetic energy than the car. Kinetic energy is calculated as KE = 0.5 * mass * velocity^2. Since both vehicles are traveling at the same speed, the one with greater mass (the car) will have more kinetic energy. The bicycle, being lighter than the car, will have less kinetic energy despite moving at the same speed. Other choices are incorrect because A is false as explained, C is incorrect as the vehicles have different masses, and D is incorrect as both vehicles are in motion, so both have kinetic energy.