#alevel #paper4 #edexcel #electricfield #ial #pearson #phyics #unit4 #jan2022

Summary

The video explains the electrostatic repulsion between two negatively charged balloons suspended by threads. Initially touching, the balloons repel after charging, causing the distance between them to increase from 0.21 meters to 0.47 meters. The shift in position leads to a calculated angle of 6.12 degrees, derived from the geometry of the setup. A free body diagram illustrates the forces acting on one balloon, including tension and weight. The tension is calculated using the mass of the balloon, and the repulsive force is determined to be approximately 2.1 × 10⁻³ N, illustrating fundamental principles of electrostatics.

Takeaways

• 😀 The surface of a balloon can become charged by rubbing it against clothing.
• 😀 The charge on the balloon is assumed to act as if it were concentrated at the balloon's center.
• 😀 Two balloons suspended by cotton threads will repel each other when given an equal negative charge.
• 😀 Initially, the distance between the two balloons was 0.21 m before the repulsion occurred.
• 😀 After repulsion, the distance between the balloons increased to 0.47 m, resulting in a shift of 0.26 m.
• 😀 The individual shift for each balloon is 0.13 m, as the total shift is divided equally.
• 😀 The angle of shift between the balloons can be calculated using trigonometry, specifically the sine of the angle.
• 😀 The angle of displacement between the balloons after repulsion is 6.12 degrees.
• 😀 A free body diagram helps visualize the forces acting on each balloon, including the repulsive force and tension in the thread.
• 😀 The tension in the thread is calculated using the weight of the balloon and the angle of displacement, resulting in a value of 0.01085 N.
• 😀 The repulsive force between the balloons is found to be approximately 0.01157 N, which is about 1 x 10^-3 N.

Q & A

What happens to the balloons when they are rubbed against clothing?

The balloons become negatively charged due to the rubbing, allowing them to repel each other when brought close together.

How does the charge on the surface of the balloon affect its behavior?

The charge can be assumed to act as if it is concentrated at the center of the balloon, leading to electrostatic repulsion between similarly charged balloons.

What is the initial distance between the two balloons?

The initial distance between the two balloons is 0.21 meters.

What occurs after the balloons are charged?

Once charged, the balloons repel each other, causing them to move apart and change their position.

What is the new distance between the balloons after charging?

The new distance between the balloons after repulsion is 0.47 meters.

How is the distance shifted calculated?

The total distance shifted is calculated as the difference between the new distance (0.47 m) and the initial distance (0.21 m), resulting in a shift of 0.26 m, with each balloon shifting 0.13 m.

What method is used to find the angle of shift (θ)?

The angle of shift is found using trigonometry, specifically the sine function in a right triangle formed by the distances involved.

What is the formula for calculating tension (T) in the system?

Tension is calculated using the formula T = mg / cos(θ), where m is the mass of the balloon and θ is the angle of shift.

What values are used to find the tension in this scenario?

The mass of the balloon is 1.1 grams (converted to kilograms as 1.1 x 10^-3 kg) and the gravitational acceleration is 9.81 m/s², along with the angle of shift, 6.12 degrees.

What is the calculated value of the repulsive force (F_R) between the balloons?

The calculated value of the repulsive force is approximately 0.01157 Newtons, which is equivalent to 1 x 10^-3 Newtons.