2 Gelombang

Summary

This video explains the fundamentals of waves, covering topics such as types of waves, wave components, and wave propagation. It introduces transverse waves, where the direction of propagation is perpendicular to the direction of vibration, and longitudinal waves, where both directions are aligned. The script also discusses wave behavior, including standing waves, traveling waves, and mechanical versus electromagnetic waves. Lastly, it provides a formula for wave speed (v = f * λ) and demonstrates its application through an example problem involving frequency, wave length, and wave speed.

Takeaways

• 😀 Waves are vibrations that propagate, transferring energy from one location to another.
• 😀 Transverse waves travel perpendicular to the direction of vibration. For example, if the vibration is vertical, the wave travels horizontally.
• 😀 In transverse waves, a valley (trough) and a peak (crest) together form one complete wave.
• 😀 The wavelength of a transverse wave is the distance between one valley and one peak, denoted by the Greek letter lambda (λ).
• 😀 Longitudinal waves have vibrations in the same direction as the wave propagation, either both horizontal or both vertical.
• 😀 Longitudinal waves are made up of compressions and rarefactions, which alternate along the wave.
• 😀 One complete longitudinal wave consists of one compression and one rarefaction, with the distance between them representing the wavelength.
• 😀 Waves can be classified as traveling waves, where the amplitude remains constant at each point, and standing waves, where the amplitude changes (e.g., guitar strings).
• 😀 Mechanical waves require a medium for propagation (e.g., sound waves or waves on water), whereas electromagnetic waves can propagate through a vacuum (e.g., light waves).
• 😀 The speed of a wave can be calculated using the formula v = f × λ, where v is the wave speed, f is the frequency, and λ is the wavelength.
• 😀 An example problem illustrates the use of the formula to calculate the frequency of a wave given its speed and wavelength. In this case, a wave with a wavelength of 0.75 m and speed of 150 m/s has a frequency of 200 Hz.

Q & A

What is the definition of a wave?

A wave is a vibration that propagates, carrying energy from one place to another.

What are the two main types of waves based on their direction of vibration?

The two main types are transversal waves and longitudinal waves. In transversal waves, the vibration is perpendicular to the direction of wave propagation, while in longitudinal waves, the vibration is parallel to the direction of wave propagation.

What is the difference between a valley and a crest in a transversal wave?

In a transversal wave, a valley (lembah) is the lowest point of the wave, while a crest (bukit) is the highest point. One full wave cycle consists of one valley and one crest.

How do we define the wavelength in a transversal wave?

The wavelength (denoted by λ) in a transversal wave is defined as the distance between one valley and one crest, or one complete cycle of the wave.

What are compressions and rarefactions in a longitudinal wave?

In a longitudinal wave, compressions (rapatan) are the areas where the particles are closest together, while rarefactions (regangan) are the areas where the particles are spread apart.

How is the wavelength defined in a longitudinal wave?

In a longitudinal wave, the wavelength (λ) is the distance between one compression and one rarefaction, forming one complete wave cycle.

What is the difference between a traveling wave and a standing wave?

A traveling wave has a constant amplitude at every point it passes, while a standing wave has an amplitude that changes depending on the point in the wave, such as in a vibrating guitar string.

What is the main difference between mechanical and electromagnetic waves?

Mechanical waves require a medium to propagate, such as sound waves or water waves, whereas electromagnetic waves do not need a medium, like light waves.

What is the formula for calculating the speed of a wave?

The speed of a wave (v) can be calculated using the formula: v = f × λ, where f is the frequency and λ is the wavelength.

In the given example, how do we calculate the frequency of a wave with a wavelength of 0.75 m and a wave speed of 150 m/s?

Using the formula v = f × λ, we rearrange it to f = v / λ. Substituting the given values, f = 150 m/s ÷ 0.75 m, which gives a frequency of 200 Hz.