# Finding Charge & Tension of a Suspended Cork Ball

• amyc
In summary: Thank you for pointing that out! In summary, the problem involves a charged cork ball suspended on a light string in the presence of a uniform electric field with a magnitude of 3×10^5 N/C in the i direction and 5×10^5 N/C in the j direction. The ball is in equilibrium and the goal is to find the charge on the ball and the tension of the string. Using equations Tsin(theta)=FEx, Tcos(theta)+FEy=mg, and F=Eq, the charge on the ball is found to be 7.6382nC and the tension of the string is 0.003808N, with proper rounding for significant figures.
amyc

## Homework Statement

A charged cork ball is suspended on a light string in the presence of a uniform electric field.
E=(3×10^5 N/C)i+(5×10^5 N/C)j. The ball is in equilibrium in the field.
Find the charge on the ball. The acceleration due to gravity is 9.8 m/s2 . The mass of the ball is 0.7g. The length of the string is 1.4m and at an angle of 37 degrees from the center.

Also find the tension of the string.

## Homework Equations

Tsin(theta)=FEx
Tcos(theta)+FEy=mg
F=Eq

## The Attempt at a Solution

Will someone please let me know if my solution and answer is correct?

Tsin(37)=(3*10^5)q
Tcos(37)+(5*10^5)q=(.0007)(9.8)
T=(3*10^5)q/sin(37)
(3*10^5)q*cot(37) + (5*10^5)q = .00686
Solve for q and q=7.6382nC

T=(3*10^5)q/sin(37) plug in q and T=.003808N

Last edited by a moderator:
It looks good. You might have put in some comments regarding what you were accomplishing or doing at each step in order to make your thought process clear. Otherwise, very well done!

@gneill Thanks! I will definitely do so next time :)

amyc said:
q=7.6382nC
Several of the given numbers are only to one significant figure, so technically you should give the answer as 8nC.

## 1. How do you determine the charge of a suspended cork ball?

The charge of a suspended cork ball can be determined by using Coulomb's Law, which states that the force between two charged objects is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. By measuring the distance between the suspended cork ball and a known charged object, and observing the force of attraction or repulsion between them, the charge of the cork ball can be calculated.

## 2. What equipment is needed to find the charge of a suspended cork ball?

To find the charge of a suspended cork ball, you will need a cork ball, a string or thread, a stand to suspend the ball from, a source of charge (such as a charged rod), and a ruler or measuring tape to measure the distance between the ball and the source of charge. A balance or scale may also be necessary to measure the mass of the cork ball.

## 3. Can the charge of a suspended cork ball be negative?

Yes, the charge of a suspended cork ball can be negative. This can occur if the cork ball becomes negatively charged by gaining electrons, or if it is suspended near a positively charged object and experiences an attractive force towards it. The charge of the cork ball will depend on the charge of the object it is suspended near.

## 4. How can you determine the tension in the string of a suspended cork ball?

The tension in the string of a suspended cork ball can be determined by using Newton's Second Law, which states that the net force on an object is equal to its mass multiplied by its acceleration. By measuring the mass of the cork ball and the acceleration due to gravity, the tension in the string can be calculated using the equation T = mg, where T is the tension, m is the mass, and g is the acceleration due to gravity.

## 5. Why is it important to find the charge and tension of a suspended cork ball?

Finding the charge and tension of a suspended cork ball can provide valuable information about the behavior of electric charges and forces. This can be applied in various fields such as physics, engineering, and telecommunications. Additionally, understanding the properties of charged objects can help us better understand and manipulate our environment.

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