Explanation

An echo is caused by the reflection of sound waves off a surface or object.

When sound waves reach a surface, some of the energy is reflected back, creating an echo.

This reflected sound wave then travels back to the listener, arriving later than the original sound, causing the echo effect.

Explanation

Ultrasound has several medical applications, including:

• Pre-natal scanning
• Diagnostic imaging
• Cancer treatment

In industry, ultrasound is used for:

• Cleaning and deburring
• Welding and bonding
• Non-destructive testing

Explanation

The order of speed of sound in different mediums, from fastest to slowest, is:

• Solid (approximately 3000-6000 m/s)
• Liquid (approximately 1000-3000 m/s)
• Gas (approximately 300-400 m/s)

Explanation

The speed of sound in air is affected by two main factors:

1. Temperature: As temperature increases, the speed of sound increases. This is because warmer air is less dense, allowing sound waves to travel faster.
2. Humidity: As humidity increases, the speed of sound decreases slightly. This is because water vapor in the air adds mass to the air molecules, making them slightly heavier and slower.

Explanation

Sound travels faster in solids than in gases because the molecules in a solid are packed more tightly together, allowing the energy to be transferred more efficiently.

In contrast, in a gas, the molecules are spaced farther apart and are free to move randomly, making it harder for the sound wave to propagate.

Explanation

Sound is a form of mechanical energy that is produced by vibrations or oscillations of particles in a medium, such as air, water, or solids.

When an object vibrates, it creates a disturbance in the medium around it, causing the particles to oscillate back and forth.

This oscillation, or wave motion, is what we perceive as sound.

Explanation

Oscillations are damped due to the presence of frictional force.

Frictional force opposes motion and converts some of the kinetic energy into heat energy, causing the oscillations to decay over time.

There are three main types of frictional force that can cause damping:

• Viscous damping (e.g., air resistance, water resistance)
• Coulomb damping (e.g., friction between surfaces)
• Internal damping (e.g., within the material itself)

Explanation

In the ball and bowl system, the mean position (also known as the equilibrium position) is at the center of the bowl.

This is the position where the ball comes to rest when it is not disturbed.

Explanation

In an oscillating pendulum, the bob accelerates from its extreme position due to the gravitational force acting on it.

The gravitational force pulls the bob towards the equilibrium position, causing it to accelerate.

Explanation

In simple harmonic motion (SHM), the object's maximum speed occurs when it passes through the equilibrium point, which is the midpoint of its oscillation.