FISIKA KELAS XI - GELOMBANG (PART 3) | Gelombang Stasioner Ujung Tertutup dan Ujung Terbuka

Summary

In this educational video on physics, Yusuf Made explores the topic of stationary waves, focusing on the differences between closed-end and open-end stationary waves. He explains how they are formed by the combination of incident and reflected waves, detailing their amplitude, nodes, and antinodes. The video goes further into formulas and examples for calculating these characteristics, such as the position of nodes and antinodes in both cases. Additionally, Yusuf provides a step-by-step guide to solving related problems, demonstrating how to find the wave's frequency, wavelength, velocity, and node positions, making the complex subject more approachable and easier to understand.

Takeaways

• 😀 Gelombang stasioner is a wave with a fixed amplitude, formed by the combination of incident and reflected waves.
• 😀 In a stationary wave with a closed end, the reflected wave is fixed, and the displacement equation is: Y = 2a sin(kx) cos(ωt).
• 😀 At a closed end, the wave has a node (zero displacement) at the reflection point, with antinodes forming at regular intervals.
• 😀 Antinodes (perut) appear at distances of 1/4λ, 3/4λ, 5/4λ, etc., from the reflecting end, whereas nodes (simpul) are at 0, 1/2λ, 1λ, 3/2λ, etc.
• 😀 For a closed-end wave, the position of the nth antinode is 2n - 1/4λ, and the nth node is n - 1/2λ.
• 😀 A wave with an open end will have a free end, where the displacement equation is: Y = 2a cos(kx) sin(ωt).
• 😀 In an open-end wave, antinodes are positioned at the reflection point, with the nodes formed at 1/4λ, 3/4λ, etc.
• 😀 For an open-end wave, the position of the nth antinode is n - 1/2λ, and the nth node is 2n - 1/4λ.
• 😀 The main difference between stationary waves at open and closed ends is the use of sine and cosine functions in their respective equations.
• 😀 A problem-solving approach is demonstrated using the example of a wave traveling along a string, where the wave type and key parameters such as frequency, wavelength, and wave speed are calculated.
• 😀 The distance between the second node and the reflecting end is calculated using the formula for nodes and antinodes in an open-end wave, with the final result being 0.3 m.

Q & A

What is a stationary wave?

A stationary wave is a wave that has a constant amplitude and is formed by the superposition of two waves traveling in opposite directions, one being the incident wave and the other the reflected wave.

What happens at the closed-end of a stationary wave?

At the closed-end (or fixed end) of a stationary wave, the wave reflects and forms a node, where the displacement is zero.

What is the formula for stationary waves with a closed end?

The formula for stationary waves at a closed end is Y = 2A sin(kx) cos(ωt), where A is the amplitude, k is the wave number, x is the position, ω is the angular frequency, and t is the time.

What are 'antinodes' and 'nodes' in a stationary wave?

Antinodes are points of maximum displacement (the peaks of the wave), while nodes are points where there is no displacement, occurring where the two waves cancel each other out.

How can the positions of nodes and antinodes be determined for a stationary wave?

For a stationary wave with a closed end, the nodes occur at integer multiples of half the wavelength, and the antinodes occur at odd multiples of a quarter wavelength.

What is the relationship between nodes and antinodes in terms of wavelength?

The distance between two consecutive nodes or antinodes is half the wavelength (λ/2). The distance between an antinode and the nearest node is a quarter of the wavelength (λ/4).

What are the main differences between stationary waves at a closed end and an open end?

At a closed end, there is a node at the fixed point, and the antinodes are located at a distance of λ/4, 3λ/4, etc., from the closed point. At an open end, the wave has an antinode at the open end, and the nodes appear at λ/4, 3λ/4, etc., from the open point.

What is the equation for stationary waves at an open end?

The formula for stationary waves at an open end is Y = 2A cos(kx) sin(ωt), where A is the amplitude, k is the wave number, x is the position, ω is the angular frequency, and t is the time.

How do you determine the position of nodes and antinodes for a stationary wave at an open end?

For a stationary wave at an open end, the antinode is at the open end, and the nodes occur at λ/4, 3λ/4, etc., from the open point.

How can the frequency of a wave be calculated from its equation?

The frequency (f) can be calculated using the angular frequency (ω), where ω = 2πf. By rearranging the equation, the frequency can be found as f = ω / 2π.