Nursing Elites

1. A pitcher throws a 45-g baseball at a velocity of 42 meters per second. What is the ball’s momentum?

• A. 0.189 kg⋅m/s
• B. 1.89 kg⋅m/s
• C. 1.07 kg⋅m/s
• D. 0.93 kg⋅m/s

Correct answer: B

Rationale: Momentum is calculated by multiplying mass (in kg) by velocity (in m/s). The mass of the baseball is 0.045 kg (45 grams converted to kg), and the velocity is 42 m/s. Momentum = 0.045 kg × 42 m/s = 1.89 kg⋅m/s. Therefore, the correct answer is 1.89 kg⋅m/s. Choice A is incorrect as it incorrectly converts the mass from grams to kg. Choice C and D are incorrect due to calculation errors.

2. The buoyant force, F_b, experienced by an object submerged in a fluid is given by:

• A. F_b = W, the object's weight
• B. F_b = W_d, the weight of the fluid displaced by the object
• C. F_b = ρ, the density of the fluid
• D. F_b = V, the object's volume

Correct answer: B

Rationale: The correct formula for the buoyant force experienced by an object submerged in a fluid is given by Archimedes' principle, which states that the buoyant force is equal to the weight of the fluid displaced by the object. This is represented by the formula F_b = W_d, where W_d is the weight of the fluid displaced by the object. This force acts in the opposite direction to gravity and is responsible for objects floating or sinking in fluids. Choice A is incorrect because the buoyant force is not equal to the object's weight. Choice C is incorrect because the density of the fluid is not directly related to the buoyant force. Choice D is incorrect because the object's volume is not the determining factor for the buoyant force.

3. What is the mathematical expression for work (W)?

• A. W = F / d
• B. W = F x d
• C. W = d / F
• D. W = F^2 x d

Correct answer: B

Rationale: The correct formula for work (W) is given by the equation W = F x d, where F represents force and d represents the displacement in the direction of the force. Work is calculated by multiplying the force applied by the distance over which the force is applied. Choice A (W = F / d) is incorrect as work is not calculated by dividing force by distance. Choice C (W = d / F) is incorrect because work is not calculated by dividing distance by force. Choice D (W = F^2 x d) is incorrect as work is not calculated by squaring the force and then multiplying by distance.

4. When two identical charged spheres, both positively charged, are brought close together, the electrostatic force between them will be:

• A. Slightly attractive
• B. Zero
• C. Strongly attractive
• D. Strongly repulsive

Correct answer: D

Rationale: When two positively charged spheres are brought close together, they will experience a repulsive force due to their like charges. The electrostatic force causes the spheres to repel each other, making the correct answer D: Strongly repulsive. The force is not dependent on the material of the spheres, and the force is definitely not zero, as like charges repel. Choice A is incorrect as like charges do not attract each other. Choice C is incorrect as like charges repel, not attract.

5. A wave moves through its medium at 20 m/s with a wavelength of 4 m. What is the frequency of the wave?

• A. 5 s−1
• B. 16 s−1
• C. 24 s−1
• D. 80 s−1

Correct answer: C

Rationale: The formula to calculate the frequency of a wave is given by:

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