Mudah Mengerjakan Soal Gelombang Dawai || Fisika Kelas XI || #oprekmafiki #fisikasma #fisikaasyik

Summary

In this tutorial, the presenter explains various physics problems related to wave motion on strings. Using formulas for wave speed, tension, and mass, the script guides viewers through solving problems involving the fundamental frequency of vibrating strings. Examples include calculating the frequency of a string based on its tension and length, and finding the mass of a string based on its vibration properties. The content offers clear, step-by-step instructions to help viewers understand how to approach these types of wave-related problems in physics.

Takeaways

• 😀 The video explains various wave-related problems using strings, focusing on transversal wave concepts.
• 😀 The first problem involves calculating the fundamental frequency of a string with a given tension, length, and wave speed.
• 😀 The formula for the fundamental frequency (f₀) is derived as v = f₀ × 2L, where v is the wave speed and L is the length of the string.
• 😀 The second problem calculates the fundamental frequency of a piano string using its length, mass, and tension.
• 😀 The formula for the fundamental frequency (f₀) is f₀ = (1/2L) × √(F/μ), where F is the tension, L is the length, and μ is the mass per unit length.
• 😀 The third problem introduces the first harmonic of a string under tension, calculating the frequency using the relationship f₁ = 2f₀.
• 😀 The calculation of f₁ involves the frequency equation f₁ = (1/2L) × √(F/μ), where the appropriate values are substituted for length, mass, and tension.
• 😀 The fourth problem calculates the mass of a string vibrating with 10 antinodes at a frequency of 500 Hz, using the known tension and length of the string.
• 😀 The relationship between the number of antinodes (modes) and frequency is used to determine the string's mass from the fundamental frequency.
• 😀 The final takeaway emphasizes the importance of using wave and string theory to solve real-world physics problems, highlighting key formulas for frequency calculation.

Q & A

What is the formula used to calculate the fundamental frequency of a vibrating string?

The formula to calculate the fundamental frequency (f0) of a vibrating string is f0 = v / 2L, where v is the wave velocity and L is the length of the string.

In the first problem, how is the fundamental frequency (f0) calculated for a string with a length of 0.8 meters and a wave speed of 400 m/s?

Using the formula f0 = v / 2L, with v = 400 m/s and L = 0.8 m, we get f0 = 400 / (2 * 0.8) = 250 Hz.

What is the importance of the fundamental frequency in the context of string vibrations?

The fundamental frequency is the lowest frequency at which a string vibrates, and it forms the basis of all harmonic frequencies on the string. It is determined by the string's length, tension, and mass.

In the second problem, how do you calculate the fundamental frequency given a string length of 0.5 m, mass of 10 grams, and a tension of 200 N?

The fundamental frequency f0 can be calculated using the formula f0 = (1/2L) * sqrt(F / m), where L is the length of the string, F is the tension, and m is the mass. Substituting values, f0 = (1 / (2 * 0.5)) * sqrt(200 / 0.01) = 100 Hz.

What does the term 'perut' mean in the context of this script?

'Perut' refers to the 'nodes' or 'antinodes' of the vibrating string, essentially points where the vibration is either at maximum displacement (antinodes) or zero displacement (nodes). In this case, it describes the number of complete wave cycles or standing waves formed on the string.

How does tension affect the fundamental frequency of a string?

The tension in a string directly affects its wave speed, and thus the fundamental frequency. Higher tension increases the wave speed, leading to a higher fundamental frequency.

How do you calculate the frequency of the first overtone (F1) of a string?

The frequency of the first overtone (F1) is calculated using the formula F1 = 2 * f0, where f0 is the fundamental frequency. The first overtone corresponds to the second harmonic of the string.

In the third problem, how is the first overtone frequency (F1) calculated for a string with a length of 0.8 meters, tension of 800 N, and mass of 16 grams?

Using the formula for the fundamental frequency and then applying the relationship F1 = 2 * f0, we first calculate f0 and then double it to find F1.

What is the significance of the relationship between the frequency and the number of nodes (perut) on the string?

The number of nodes (perut) indicates the harmonic number and affects the frequency of the string’s vibrations. The more nodes there are, the higher the frequency of the vibration.

In the fourth problem, how is the mass of the string calculated when given the frequency of the 10th harmonic and tension?

The mass of the string is calculated by rearranging the formula for the fundamental frequency and using the known values for tension and harmonic frequency. The result gives the mass of the string, which is 10 grams in this case.