# What Determines the Repulsion Between Two Positively Charged Spheres?

• Ry122
In summary, the force between two charges can be calculated using Coulomb's Law, which states that it is equal to the product of the two charges divided by the distance between them squared. The magnitude of the force decreases as the distance between the charges increases, and the unit of measurement for this force is the Newton (N). The force can be either attractive or repulsive, depending on the charges involved. If the charges are of opposite signs, the force between them will increase as the distance remains the same.
Ry122
Each of two small non-conducting spheres is charged positively, the combined charge being 40C . When the two spheres are 50 cm apart, each sphere is repelled from the other by a force of magnitude 2.5 N. Determine the magnitude of the smaller of the two charges

my attempt:
use eq. F=kq1q2/d
2.5=((9x10^9)(40-q2)(q2))/.5
this gives me the wrong answer
what am i doing wrong?

You forgot r is square.

It seems like you have set up the equation correctly, but you may have made a mistake in your calculations or in the units used. Here is a step-by-step solution using the given information:

1. First, we need to convert the distance between the two spheres from centimeters to meters, since the equation for force uses meters as the unit of distance. 50 cm = 0.5 m.

2. Next, we can plug in the given values into the equation for force:
2.5 N = (9x10^9 N*m^2/C^2)(40 C)(q2 C)/ (0.5 m)^2

3. Simplifying, we get:
2.5 N = 720 C^2(q2 C)/ 0.25 m^2

4. Rearranging the equation to solve for q2:
q2 = (2.5 N * 0.25 m^2)/ (720 C^2) = 8.33x10^-7 C

Therefore, the magnitude of the smaller of the two charges is approximately 8.33x10^-7 C. Double check your calculations and units to ensure accuracy.

## 1. What is the formula for calculating the force between two charges?

The force between two charges can be calculated using Coulomb's Law, which states that the force (F) is equal to the product of the two charges (q1 and q2) divided by the distance between them squared (r2). Mathematically, it can be written as F = (q1q2)/r2.

## 2. How does the magnitude of the force change as the distance between the two charges increases?

The magnitude of the force between two charges is inversely proportional to the square of the distance between them. This means that as the distance increases, the force decreases. So, the farther apart the two charges are, the weaker the force between them will be.

## 3. What is the unit of measurement for the force between two charges?

The unit of measurement for the force between two charges is the Newton (N). This is the same unit used to measure other types of forces, such as weight and gravitational force.

## 4. Can the force between two charges be attractive or repulsive?

Yes, the force between two charges can be either attractive or repulsive. Like charges (positive and positive or negative and negative) will repel each other, while opposite charges (positive and negative) will attract each other.

## 5. How does the force between two charges change if the charges are of opposite signs but the distance between them remains the same?

If the distance between two charges remains the same but the charges are of opposite signs, the force between them will increase. This is because the charges are now attracting each other instead of repelling, making the force stronger.

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