Exam 8 Target 3 Retake Preap

1. Gravitational force and electrical force are alike in what ways?

A. They depend on charge.

B. They are field forces.

C. They act only when objects are touching.

D. They depend on mass.

Gravitational force and electrical force are alike in that they are both field forces. This means that they can act on objects even when they are not in direct contact with each other. Field forces are forces that are exerted through a field, such as the gravitational field or the electric field. Both gravitational and electrical forces can act over a distance, without the need for physical contact between objects. Therefore, the correct answer is b. They are field forces.

Explanation

Gravitational force and electrical force are alike in that they are both field forces. This means that they can act on objects even when they are not in direct contact with each other. Field forces are forces that are exerted through a field, such as the gravitational field or the electric field. Both gravitational and electrical forces can act over a distance, without the need for physical contact between objects. Therefore, the correct answer is b. They are field forces.

2. Which of the choices below best represent a difference between electric force and gravitational force?

A. Electric force is inversely proportional to the square of the distance between objects.

B. Gravitational force is stronger than electric force.

C. Electric force can both attract and repel.

D. Gravitational force exists between objects that are not touching.

The correct answer is c. Electric force can both attract and repel. This is a key difference between electric force and gravitational force. Electric force can either attract or repel depending on the charges of the objects involved. Objects with like charges repel each other, while objects with opposite charges attract each other. On the other hand, gravitational force only attracts objects and does not have a repelling effect.

Explanation

The correct answer is c. Electric force can both attract and repel. This is a key difference between electric force and gravitational force. Electric force can either attract or repel depending on the charges of the objects involved. Objects with like charges repel each other, while objects with opposite charges attract each other. On the other hand, gravitational force only attracts objects and does not have a repelling effect.

3. Two 3 kg spheres each carry a charge of magnitude 3 C. How does F_E, the strength of the electric force between the spheres, compare with F_G, the strength of their gravitational attraction?

A. FE > FG

B. FE < FG

C. FE = FG

E. Cannot be determined without knowing the distance between the spheres

The electric force between the spheres, FE, is greater than the gravitational attraction between them, FG. This is because the magnitude of the electric force is determined by the product of the charges (3 C x 3 C = 9 C^2) divided by the square of the distance between the spheres, while the magnitude of the gravitational attraction is determined by the product of the masses (3 kg x 3 kg = 9 kg^2) divided by the square of the distance between the spheres. Since the charges have a larger magnitude than the masses, the electric force is stronger than the gravitational attraction.

Explanation

The electric force between the spheres, FE, is greater than the gravitational attraction between them, FG. This is because the magnitude of the electric force is determined by the product of the charges (3 C x 3 C = 9 C^2) divided by the square of the distance between the spheres, while the magnitude of the gravitational attraction is determined by the product of the masses (3 kg x 3 kg = 9 kg^2) divided by the square of the distance between the spheres. Since the charges have a larger magnitude than the masses, the electric force is stronger than the gravitational attraction.

4. When comparing the force of attraction between an electron and a proton due to the electric force and gravity, it can be concluded that

A. the gravitational force is a lot stronger

B. the electric force is a lot stronger

C. the two types of forces are the same

D. they cannot be compared

E. the electric force is slightly stronger

The explanation for the correct answer is that the electric force between an electron and a proton is much stronger than the force of gravity between them. This is because the electric force is determined by the charge of the particles, whereas gravity is determined by the mass of the particles. Since the charge of an electron and a proton is much larger than their mass, the electric force dominates and is much stronger than gravity in this scenario.

Explanation

The explanation for the correct answer is that the electric force between an electron and a proton is much stronger than the force of gravity between them. This is because the electric force is determined by the charge of the particles, whereas gravity is determined by the mass of the particles. Since the charge of an electron and a proton is much larger than their mass, the electric force dominates and is much stronger than gravity in this scenario.

5. Which of the following is not true for both gravitational and electric forces?

A. Forces are either attractive or repulsive.

B. The inverse square distance law applies.

C. Forces are proportional to physical properties.

D. Potential energy is a function of distance of separation.

Both gravitational and electric forces are always either attractive or repulsive. Gravitational force is attractive, meaning it pulls objects towards each other, while electric force can be either attractive or repulsive depending on the charges of the objects involved. Therefore, option a is not true for both forces.

Explanation

Both gravitational and electric forces are always either attractive or repulsive. Gravitational force is attractive, meaning it pulls objects towards each other, while electric force can be either attractive or repulsive depending on the charges of the objects involved. Therefore, option a is not true for both forces.